Add GrGpu support for Vulkan command buffer flush

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1705133002

Review URL: https://codereview.chromium.org/1705133002

src/gpu/GrDrawTarget.cpp

@@ -214,7 +214,7 @@ void GrDrawTarget::drawBatches(GrBatchFlushState* flushState) {
         fBatches[i]->draw(flushState);
     }
 
-    fGpu->performFlushWorkaround();
+    fGpu->finishDrawTarget();
 }
 
 void GrDrawTarget::reset() {

src/gpu/GrGpu.cpp

@@ -369,9 +369,6 @@ void GrGpu::resolveRenderTarget(GrRenderTarget* target) {
     this->onResolveRenderTarget(target);
 }
 
-void GrGpu::performFlushWorkaround() {
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrGpu::draw(const DrawArgs& args, const GrVertices& vertices) {

src/gpu/GrGpu.h

@@ -349,8 +349,9 @@ public:
 
     void draw(const DrawArgs&, const GrVertices&);
 
-    // Called by drawtarget when flushing. Provides a hook for working around an ARM PLS driver bug.
-    virtual void performFlushWorkaround();
+    // Called by drawtarget when flushing. 
+    // Provides a hook for post-flush actions (e.g. PLS reset and Vulkan command buffer submits).
+    virtual void finishDrawTarget() {}
 
     ///////////////////////////////////////////////////////////////////////////
     // Debugging and Stats

src/gpu/gl/GrGLGpu.cpp

@@ -2427,7 +2427,7 @@ bool GrGLGpu::onReadPixels(GrSurface* surface,
     return true;
 }
 
-void GrGLGpu::performFlushWorkaround() {
+void GrGLGpu::finishDrawTarget() {
     if (fPLSHasBeenUsed) {
         /* There is an ARM driver bug where if we use PLS, and then draw a frame which does not 
          * use PLS, it leaves garbage all over the place. As a workaround, we use PLS in a 

src/gpu/gl/GrGLGpu.h

@@ -134,7 +134,7 @@ public:
 
     void drawDebugWireRect(GrRenderTarget*, const SkIRect&, GrColor) override;
 
-    void performFlushWorkaround() override;
+    void finishDrawTarget() override;
 
 private:
     GrGLGpu(GrGLContext* ctx, GrContext* context);