Improve tracking of bound FBOs in GrGLGpu.

src/gpu/gl/GrGLCaps.h

Index: src/gpu/gl/GrGLCaps.h
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 1b77ed0e3204099847b26decf6c6a5ddb8753904..932e66fdfc160a573645916e2596cbc66d4e34b9 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -267,6 +267,10 @@ public:
     bool fullClearIsFree() const { return fFullClearIsFree; }
 
     bool dropsTileOnZeroDivide() const { return fDropsTileOnZeroDivide; }
+    
+    bool preferBindingToReadAndDrawFramebuffer() const {
+        return fPreferBindingToReadAndDrawFramebuffer;
+    }
 
     /**
      * Returns a string containing the caps info.
@@ -389,6 +393,7 @@ private:
     bool fDropsTileOnZeroDivide : 1;
     bool fFBFetchSupport : 1;
     bool fFBFetchNeedsCustomOutput : 1;
+    bool fPreferBindingToReadAndDrawFramebuffer : 1;
 
     const char* fFBFetchColorName;
     const char* fFBFetchExtensionString;