Add flag bits for partial GrContext reset

include/gpu/GrContext.h

Index: include/gpu/GrContext.h
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index 5c796b26c034833348014bf558b8d0700115aebf..d2a95c6524356661cc6850c902f26ef76ba19344 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -56,13 +56,32 @@ public:
 
     virtual ~GrContext();
 
+    enum GrState {

[bsalomon, 2013/06/18 10:16:32]

For enums that are nested within a class we don't typically prefix them by Gr. I
think we either should move this to GrTypes or remove the Gr prefix.

Also in Skia the name of the enum comes last in enum values. So kTexture_GrState
rather than kGrState_Texture.

State seems a little bit vague, we're using the word "backend" in other places
to refer to the underlying 3D API. Could we call it "BackendState" or some
variation on that?

Also, some of this is fairly GL-specific (e.g. pixelstore) and wouldn't make
sense on a theoretical D3D backend. Why don't we make this GLBackendState, make
the function take a uint32_t, and have a comment that the flag bits are
dependent on which backend is used by the context. If we're going to possibly
have multiple sets of flags then I'd prefer to move this to GrTypes.h and keep
the Gr prefixing.

+        kGrState_RenderTarget = 0x01 << 0,
+        kGrState_Texture      = 0x01 << 1,

[bsalomon, 2013/06/18 10:16:32]

TextureBindings?

+        kGrState_View         = 0x01 << 2,

[bsalomon, 2013/06/18 10:16:32]

View could use a comment, not obvious what state it refers to.

+        kGrState_Blend        = 0x01 << 3,
+        kGrState_AA           = 0x01 << 4,
+        kGrState_Vertex       = 0x01 << 5,
+        kGrState_Stencil      = 0x01 << 6,
+        kGrState_PixelStore   = 0x01 << 7,
+        kGrState_Program      = 0x01 << 8,
+        kGrState_PathStencil  = 0x01 << 9,
+        kGrState_Misc         = 0x01 << 10,
+        kGrState_ALL          = 0xffff
+    };
     /**
      * The GrContext normally assumes that no outsider is setting state
      * within the underlying 3D API's context/device/whatever. This call informs
      * the context that the state was modified and it should resend. Shouldn't
      * be called frequently for good performance.
      */
-    void resetContext();
+    void resetContext(GrState state = kGrState_ALL);
+
+    /**
+     * Similiar to resetContext, but only reset texture binding state.
+     */
+    void resetTextureBinding();

[bsalomon, 2013/06/18 10:16:32]

Let's just stick with the one resetContext() call and not have a specialized
function. Blink can pass kTexture.

 
     /**
      * Callback function to allow classes to cleanup on GrContext destruction.