diff --git a/src/gpu/GrGeometryBuffer.h b/src/gpu/GrGeometryBuffer.h
index 1e1a367260..67e91cc4d9 100644
--- a/src/gpu/GrGeometryBuffer.h
+++ b/src/gpu/GrGeometryBuffer.h
@@ -45,42 +45,58 @@ public:
      * Currently only one map at a time is supported (no nesting of
      * map/unmap).
      *
+     * Note that buffer mapping does not go through GrContext and therefore is
+     * not serialized with other operations.
+     *
      * @return a pointer to the data or NULL if the map fails.
      */
-    virtual void* map() = 0;
-
-    /**
-     * Returns the same ptr that map() returned at time of map or NULL if the
-     * is not mapped.
-     *
-     * @return ptr to mapped buffer data or undefined if buffer is not mapped.
-     */
-    virtual void* mapPtr() const = 0;
+     void* map() { return (fMapPtr = this->onMap()); }
 
     /**
      * Unmaps the buffer.
      *
      * The pointer returned by the previous map call will no longer be valid.
      */
-    virtual void unmap() = 0;
+     void unmap() {
+         SkASSERT(NULL != fMapPtr);
+         this->onUnmap();
+         fMapPtr = NULL;
+     }
+
+    /**
+     * Returns the same ptr that map() returned at time of map or NULL if the
+     * is not mapped.
+     *
+     * @return ptr to mapped buffer data or NULL if buffer is not mapped.
+     */
+     void* mapPtr() const { return fMapPtr; }
 
     /**
      Queries whether the buffer has been mapped.
 
      @return true if the buffer is mapped, false otherwise.
      */
-    virtual bool isMapped() const = 0;
+     bool isMapped() const { return NULL != fMapPtr; }
 
     /**
      * Updates the buffer data.
      *
      * The size of the buffer will be preserved. The src data will be
      * placed at the beginning of the buffer and any remaining contents will
-     * be undefined.
+     * be undefined. srcSizeInBytes must be <= to the buffer size.
+     *
+     * The buffer must not be mapped.
+     *
+     * Note that buffer updates do not go through GrContext and therefore are
+     * not serialized with other operations.
      *
      * @return returns true if the update succeeds, false otherwise.
      */
-    virtual bool updateData(const void* src, size_t srcSizeInBytes) = 0;
+    bool updateData(const void* src, size_t srcSizeInBytes) {
+        SkASSERT(!this->isMapped());
+        SkASSERT(srcSizeInBytes <= fGpuMemorySize);
+        return this->onUpdateData(src, srcSizeInBytes);
+    }
 
     // GrGpuObject overrides
     virtual size_t gpuMemorySize() const { return fGpuMemorySize; }
@@ -88,11 +104,17 @@ public:
 protected:
     GrGeometryBuffer(GrGpu* gpu, bool isWrapped, size_t gpuMemorySize, bool dynamic, bool cpuBacked)
         : INHERITED(gpu, isWrapped)
+        , fMapPtr(NULL)
         , fGpuMemorySize(gpuMemorySize)
         , fDynamic(dynamic)
         , fCPUBacked(cpuBacked) {}
 
 private:
+    virtual void* onMap() = 0;
+    virtual void onUnmap() = 0;
+    virtual bool onUpdateData(const void* src, size_t srcSizeInBytes) = 0;
+
+    void*    fMapPtr;
     size_t   fGpuMemorySize;
     bool     fDynamic;
     bool     fCPUBacked;
diff --git a/src/gpu/gl/GrGLBufferImpl.h b/src/gpu/gl/GrGLBufferImpl.h
index 3ab84f67e2..279075f4c9 100644
--- a/src/gpu/gl/GrGLBufferImpl.h
+++ b/src/gpu/gl/GrGLBufferImpl.h
@@ -41,7 +41,6 @@ public:
     void bind(GrGpuGL* gpu) const;
 
     void* map(GrGpuGL* gpu);
-    void* mapPtr() const { return fMapPtr; }
     void unmap(GrGpuGL* gpu);
     bool isMapped() const;
     bool updateData(GrGpuGL* gpu, const void* src, size_t srcSizeInBytes);
diff --git a/src/gpu/gl/GrGLIndexBuffer.cpp b/src/gpu/gl/GrGLIndexBuffer.cpp
index 38dd15d5f6..a137348ef7 100644
--- a/src/gpu/gl/GrGLIndexBuffer.cpp
+++ b/src/gpu/gl/GrGLIndexBuffer.cpp
@@ -26,7 +26,7 @@ void GrGLIndexBuffer::onAbandon() {
     INHERITED::onAbandon();
 }
 
-void* GrGLIndexBuffer::map() {
+void* GrGLIndexBuffer::onMap() {
     if (!this->wasDestroyed()) {
         return fImpl.map(this->getGpuGL());
     } else {
@@ -34,21 +34,13 @@ void* GrGLIndexBuffer::map() {
     }
 }
 
-void* GrGLIndexBuffer::mapPtr() const {
-    return fImpl.mapPtr();
-}
-
-void GrGLIndexBuffer::unmap() {
+void GrGLIndexBuffer::onUnmap() {
     if (!this->wasDestroyed()) {
         fImpl.unmap(this->getGpuGL());
     }
 }
 
-bool GrGLIndexBuffer::isMapped() const {
-    return fImpl.isMapped();
-}
-
-bool GrGLIndexBuffer::updateData(const void* src, size_t srcSizeInBytes) {
+bool GrGLIndexBuffer::onUpdateData(const void* src, size_t srcSizeInBytes) {
     if (!this->wasDestroyed()) {
         return fImpl.updateData(this->getGpuGL(), src, srcSizeInBytes);
     } else {
diff --git a/src/gpu/gl/GrGLIndexBuffer.h b/src/gpu/gl/GrGLIndexBuffer.h
index 3960f58437..5d5de43eee 100644
--- a/src/gpu/gl/GrGLIndexBuffer.h
+++ b/src/gpu/gl/GrGLIndexBuffer.h
@@ -31,19 +31,15 @@ public:
         }
     }
 
-    // overrides of GrIndexBuffer
-    virtual void* map() SK_OVERRIDE;
-    virtual void* mapPtr() const SK_OVERRIDE;
-    virtual void unmap() SK_OVERRIDE;
-    virtual bool isMapped() const SK_OVERRIDE;
-    virtual bool updateData(const void* src, size_t srcSizeInBytes);
-
 protected:
-    // overrides of GrResource
     virtual void onAbandon() SK_OVERRIDE;
     virtual void onRelease() SK_OVERRIDE;
 
 private:
+    virtual void* onMap() SK_OVERRIDE;
+    virtual void onUnmap() SK_OVERRIDE;
+    virtual bool onUpdateData(const void* src, size_t srcSizeInBytes) SK_OVERRIDE;
+
     GrGpuGL* getGpuGL() const {
         SkASSERT(!this->wasDestroyed());
         return (GrGpuGL*)(this->getGpu());
diff --git a/src/gpu/gl/GrGLVertexBuffer.cpp b/src/gpu/gl/GrGLVertexBuffer.cpp
index af6099353a..a13ad126ec 100644
--- a/src/gpu/gl/GrGLVertexBuffer.cpp
+++ b/src/gpu/gl/GrGLVertexBuffer.cpp
@@ -21,13 +21,12 @@ void GrGLVertexBuffer::onRelease() {
     INHERITED::onRelease();
 }
 
-
 void GrGLVertexBuffer::onAbandon() {
     fImpl.abandon();
     INHERITED::onAbandon();
 }
 
-void* GrGLVertexBuffer::map() {
+void* GrGLVertexBuffer::onMap() {
     if (!this->wasDestroyed()) {
         return fImpl.map(this->getGpuGL());
     } else {
@@ -35,21 +34,13 @@ void* GrGLVertexBuffer::map() {
     }
 }
 
-void* GrGLVertexBuffer::mapPtr() const {
-    return fImpl.mapPtr();
-}
-
-void GrGLVertexBuffer::unmap() {
+void GrGLVertexBuffer::onUnmap() {
     if (!this->wasDestroyed()) {
         fImpl.unmap(this->getGpuGL());
     }
 }
 
-bool GrGLVertexBuffer::isMapped() const {
-    return fImpl.isMapped();
-}
-
-bool GrGLVertexBuffer::updateData(const void* src, size_t srcSizeInBytes) {
+bool GrGLVertexBuffer::onUpdateData(const void* src, size_t srcSizeInBytes) {
     if (!this->wasDestroyed()) {
         return fImpl.updateData(this->getGpuGL(), src, srcSizeInBytes);
     } else {
diff --git a/src/gpu/gl/GrGLVertexBuffer.h b/src/gpu/gl/GrGLVertexBuffer.h
index ddab8299a7..db413ac990 100644
--- a/src/gpu/gl/GrGLVertexBuffer.h
+++ b/src/gpu/gl/GrGLVertexBuffer.h
@@ -31,19 +31,15 @@ public:
         }
     }
 
-    // overrides of GrVertexBuffer
-    virtual void* map() SK_OVERRIDE;
-    virtual void* mapPtr() const SK_OVERRIDE;
-    virtual void unmap() SK_OVERRIDE;
-    virtual bool isMapped() const SK_OVERRIDE;
-    virtual bool updateData(const void* src, size_t srcSizeInBytes);
-
 protected:
-    // overrides of GrResource
     virtual void onAbandon() SK_OVERRIDE;
     virtual void onRelease() SK_OVERRIDE;
 
 private:
+    virtual void* onMap() SK_OVERRIDE;
+    virtual void onUnmap() SK_OVERRIDE;
+    virtual bool onUpdateData(const void* src, size_t srcSizeInBytes) SK_OVERRIDE;
+
     GrGpuGL* getGpuGL() const {
         SkASSERT(!this->wasDestroyed());
         return (GrGpuGL*)(this->getGpu());