skia: Add support for CHROMIUM_image backed textures.

I created a new abstract base class TextureStorageAllocator that consumers of
Skia can subclass and pass back to Skia. When a surface is created with a
pointer to a TextureStorageAllocator, any textures it creates, or that are
derived from the original surface, will allocate and deallocate storage using
the methods on TextureStorageAllocator.

BUG=https://code.google.com/p/chromium/issues/detail?id=579664
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1623653002

Committed: https://skia.googlesource.com/skia/+/92098e691f10a010e7421125ba4d44c02506bb55

Committed: https://skia.googlesource.com/skia/+/7fec91ce6660190f8d7c5eb6f3061e4550cc672b

Committed: https://skia.googlesource.com/skia/+/b8d6e088590160f1198110c2371b802c1d541a36

Review URL: https://codereview.chromium.org/1623653002
diff --git a/src/gpu/SkGpuDevice.h b/src/gpu/SkGpuDevice.h
index 8bf04b1..ec3e158 100644
--- a/src/gpu/SkGpuDevice.h
+++ b/src/gpu/SkGpuDevice.h
@@ -18,6 +18,7 @@
 #include "GrDrawContext.h"
 #include "GrContext.h"
 #include "GrSurfacePriv.h"
+#include "GrTypes.h"
 
 class GrAccelData;
 class GrTextureProducer;
@@ -52,7 +53,8 @@
      * the resource cache budget. On failure, returns nullptr.
      */
     static SkGpuDevice* Create(GrContext*, SkSurface::Budgeted, const SkImageInfo&,
-                               int sampleCount, const SkSurfaceProps*, InitContents);
+                               int sampleCount, const SkSurfaceProps*,
+                               InitContents, GrTextureStorageAllocator = GrTextureStorageAllocator());
 
     ~SkGpuDevice() override {}
 
@@ -255,7 +257,7 @@
     bool drawDashLine(const SkPoint pts[2], const SkPaint& paint);
 
     static GrRenderTarget* CreateRenderTarget(GrContext*, SkSurface::Budgeted, const SkImageInfo&,
-                                              int sampleCount);
+                                              int sampleCount, GrTextureStorageAllocator);
 
     friend class GrAtlasTextContext;
     friend class SkSurface_Gpu;      // for access to surfaceProps