some catchup CL revisions

BUG=skia:

Review URL: https://codereview.chromium.org/1295593002

gm/image_pict.cpp

@@ -128,10 +128,8 @@ protected:
 
         SkMatrix matrix;
         matrix.setTranslate(-100, -100);
-        fCache.reset(new SkImageCacherator(SkImageGenerator::NewFromPicture(size,
-                                                                            fPicture,
-                                                                            &matrix,
-                                                                            nullptr)));
+        auto gen = SkImageGenerator::NewFromPicture(size, fPicture, &matrix, nullptr);
+        fCache.reset(SkImageCacherator::NewFromGenerator(gen));
     }
 
     void drawSet(SkCanvas* canvas) const {

include/core/SkImageGenerator.h

@@ -144,9 +144,9 @@ public:
      *  Regarding the SkImageUsageType parameter:
      *
      *  If the context (the provided one or the generator's intrinsic one) determines that to
-     *  support the specified usage, it must return a different sized texture (from the generator's
-     *  native size) it may, so the caller must inspect the texture's width/height
-     *  (unless kUntiled_SkImageUsedType was specified).
+     *  support the specified usage, it must return a different sized texture it may,
+     *  so the caller must inspect the texture's width/height and compare them to the generator's
+     *  getInfo() width/height.
      */
     GrTexture* generateTexture(GrContext*, SkImageUsageType);
 

src/core/SkImageCacherator.cpp

@@ -19,10 +19,17 @@
 #include "SkGrPriv.h"
 #endif
 
+SkImageCacherator* SkImageCacherator::NewFromGenerator(SkImageGenerator* gen) {
+    if (!gen) {
+        return nullptr;
+    }
+    return SkNEW_ARGS(SkImageCacherator, (gen));
+}
+
 SkImageCacherator::SkImageCacherator(SkImageGenerator* gen) : fGenerator(gen) {}
 
 SkImageCacherator::~SkImageCacherator() {
-    delete fGenerator;
+    SkDELETE(fGenerator);
 }
 
 static bool check_output_bitmap(const SkBitmap& bitmap, uint32_t expectedID) {

src/core/SkImageCacherator.h

@@ -19,7 +19,8 @@ class SkBitmap;
 class SkImageCacherator {
 public:
     // Takes ownership of the generator
-    SkImageCacherator(SkImageGenerator* gen);
+    static SkImageCacherator* NewFromGenerator(SkImageGenerator*);
+
     ~SkImageCacherator();
 
     const SkImageInfo& info() const { return fGenerator->getInfo(); }
@@ -28,8 +29,6 @@ public:
     /**
      *  On success (true), bitmap will point to the pixels for this generator. If this returns
      *  false, the bitmap will be reset to empty.
-     *
-     *  The cached bitmap is valid until it goes out of scope.
      */
     bool lockAsBitmap(SkBitmap*);
 
@@ -37,11 +36,13 @@ public:
      *  Returns a ref() on the texture produced by this generator. The caller must call unref()
      *  when it is done. Will return NULL on failure.
      *
-     *  The cached texture is valid until it is unref'd.
+     *  The caller is responsible for calling texture->unref() when they are done.
      */
     GrTexture* lockAsTexture(GrContext*, SkImageUsageType);
 
 private:
+    SkImageCacherator(SkImageGenerator* gen);
+
     bool tryLockAsBitmap(SkBitmap*);
     GrTexture* tryLockAsTexture(GrContext*, SkImageUsageType);