Adding a new SkSurface factory for generating surfaces from the scratch texture pool.

include/gpu/SkGpuDevice.h

Index: include/gpu/SkGpuDevice.h
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index 4ea67fe6203dd08951cf6150ded45742cc91c832..c7764ec5ddc76a392441898188ba53f96b192347 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -29,12 +29,18 @@ class GrTextContext;
  */
 class SK_API SkGpuDevice : public SkBitmapDevice {
 public:
+    enum Flags {
+        kNeedClear_Flag = 1 << 0,  //!< Surface requires an initial clear 
+        kCached_Flag    = 1 << 1,  //!< Surface is cached and needs to be unlocked when released
+    };
 
     /**
      * Creates an SkGpuDevice from a GrSurface. This will fail if the surface is not a render
-     * target. The caller owns a ref on the returned device.
+     * target. The caller owns a ref on the returned device. If the surface is cached, 
+     * the kCached_Flag should be specified to make the device responsible for unlocking
+     * the surface when it is released.
      */
-    static SkGpuDevice* Create(GrSurface* surface);
+    static SkGpuDevice* Create(GrSurface* surface, unsigned flags = 0);
 
     /**
      *  New device that will create an offscreen renderTarget based on the
@@ -58,7 +64,7 @@ public:
      *  DEPRECATED -- need to make this private, call Create(surface)
      *  New device that will render to the specified renderTarget.
      */
-    SkGpuDevice(GrContext*, GrRenderTarget*);
+    SkGpuDevice(GrContext*, GrRenderTarget*, unsigned flags = 0);

[bsalomon, 2014/03/19 19:15:37]

I'm wondering if this and the below one are necessary at all anymore. AFAIK
Blink makes all their gpu devices via surface (though I'm not sure about image
filters). onCreateDevice will use this after this change but it seems like it
could use Create(GrSurface*, unsigned) instead. It seems like it should do that
anyway, even if these can't be removed yet, so that we don't add a call to a
deprecated function.

 
     /**
      *  DEPRECATED -- need to make this private, call Create(surface)
@@ -66,7 +72,7 @@ public:
      *  The GrTexture's asRenderTarget() must be non-NULL or device will not
      *  function.
      */
-    SkGpuDevice(GrContext*, GrTexture*);
+    SkGpuDevice(GrContext*, GrTexture*, unsigned flags = 0);
 
     virtual ~SkGpuDevice();
 
@@ -171,10 +177,7 @@ private:
     bool                fNeedClear;
 
     // called from rt and tex cons
-    void initFromRenderTarget(GrContext*, GrRenderTarget*, bool cached);
-
-    // used by createCompatibleDevice
-    SkGpuDevice(GrContext*, GrTexture* texture, bool needClear);
+    void initFromRenderTarget(GrContext*, GrRenderTarget*, unsigned flags);
 
     virtual SkBaseDevice* onCreateDevice(const SkImageInfo&, Usage) SK_OVERRIDE;