Add deferred texture upload API.

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 832ff9dea16f48254fbe8c953d3b6b8656c8df58..1d385853634fa49272ccd5816e129f08b7f4c85a 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -25,6 +25,7 @@ class SkPixelSerializer;
 class SkString;
 class SkSurface;
 class GrContext;
+class GrContextThreadSafeProxy;
 class GrTexture;
 
 /**
@@ -324,6 +325,44 @@ public:
      */
     SkImage* newTextureImage(GrContext*) const;
 
+    /** Drawing params for which a deferred texture image data should be optimized. */
+    struct DeferredTextureImageUsageParams {
+        SkMatrix        fMatrix;
+        SkFilterQuality fQuality;
+    };
+
+    /**
+     * This method allows clients to capture the data necessary to turn a SkImage into a texture-
+     * backed image. If the original image is codec-backed this will decode into a format optimized
+     * for the context represented by the proxy. This method is thread safe with respect to the
+     * GrContext whence the proxy came. Clients allocate and manage the storage of the deferred
+     * texture data and control its lifetime. No cleanup is required, thus it is safe to simply free
+     * the memory out from under the data.
+     *
+     * The same method is used both for getting the size necessary for pre-uploaded texture data
+     * and for retrieving the data. The params array represents the set of draws over which to
+     * optimize the pre-upload data.
+     *
+     * When called with a null buffer this returns the size that the client must allocate in order
+     * to create deferred texture data for this image (or zero if this is an inappropriate
+     * candidate). The buffer allocated by the client should be 8 byte aligned.
+     *
+     * When buffer is not null this fills in the deferred texture data for this image in the
+     * provided buffer (assuming this is an appropriate candidate image and the buffer is
+     * appropriately aligned). Upon success the size written is returned, otherwise 0.
+     */
+    size_t getDeferredTextureImageData(const GrContextThreadSafeProxy&,
+                                       const DeferredTextureImageUsageParams[],
+                                       int paramCnt,
+                                       void* buffer) const;
+
+    /**
+     * Returns a texture-backed image from data produced in SkImage::getDeferredTextureImageData.
+     * The context must be the context that provided the proxy passed to

[reed1, 2016/03/10 21:34:12]

btw -- can you assert that, by storing the GrCotnext* in your data-blob ad build
time?

[bsalomon, 2016/03/10 21:37:46]

I don't assert but I do check it by storing the GrContext's unique ID and fail
if it is different.

+     * getDeferredTextureImageData.
+     */
+    static SkImage* NewFromDeferredTextureImageData(GrContext*, const void*, SkBudgeted);
+
     // Helper functions to convert to SkBitmap
 
     enum LegacyBitmapMode {