Make copySurface work in more situations.

src/gpu/gl/GrGLCaps.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef GrGLCaps_DEFINED
 #define GrGLCaps_DEFINED
@@ skipping 59 matching lines @@
          */
         kES_EXT_MsToTexture_MSFBOType,
         /**
          * GL_NV_framebuffer_mixed_samples.
          */
         kMixedSamples_MSFBOType,
 
         kLast_MSFBOType = kMixedSamples_MSFBOType
     };
 
+    enum BlitFramebufferSupport {
+        kNone_BlitFramebufferSupport,
+        /**
+         * ANGLE exposes a limited blit framebuffer extension that does not allow for stretching
+         * or mirroring.
+         */
+        kNoScalingNoMirroring_BlitFramebufferSupport,
+        kFull_BlitFramebufferSupport
+    };
+
     enum InvalidateFBType {
         kNone_InvalidateFBType,
         kDiscard_InvalidateFBType,       //<! glDiscardFramebuffer()
-        kInvalidate_InvalidateFBType,     //<! glInvalidateFramebuffer()
+        kInvalidate_InvalidateFBType,    //<! glInvalidateFramebuffer()
 
         kLast_InvalidateFBType = kInvalidate_InvalidateFBType
     };
 
     enum MapBufferType {
         kNone_MapBufferType,
         kMapBuffer_MapBufferType,         // glMapBuffer()
         kMapBufferRange_MapBufferType,    // glMapBufferRange()
         kChromium_MapBufferType,          // GL_CHROMIUM_map_sub
 
@@ skipping 101 matching lines @@
     bool isConfigVerifiedColorAttachment(GrPixelConfig config) const {
         return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kVerifiedColorAttachment_Flag);
     }
 
     /**
      * Reports the type of MSAA FBO support.
      */
     MSFBOType msFBOType() const { return fMSFBOType; }
 
     /**
-     * Does the supported MSAA FBO extension have MSAA renderbuffers?
+     * Does the preferred MSAA FBO extension have MSAA renderbuffers?
      */
     bool usesMSAARenderBuffers() const {
         return kNone_MSFBOType != fMSFBOType &&
                kES_IMG_MsToTexture_MSFBOType != fMSFBOType &&
                kES_EXT_MsToTexture_MSFBOType != fMSFBOType &&
                kMixedSamples_MSFBOType != fMSFBOType;
     }
 
     /**

[robertphillips, 2016/02/12 18:59:53]

Hmmm, this comment doesn't seem quite right. This method doesn't return
true/false.

[bsalomon, 2016/02/12 19:09:14]

Done.

+     * Is glBlitFramebuffer supported? This may be true when usesMSAARenderBuffers() is false as
+     * we may have preferred a MSAA extension that doesn't rely on glBlitFramebuffer.
+     */
+    BlitFramebufferSupport blitFramebufferSupport() const { return fBlitFramebufferSupport; }
+
+    /**
      * Is the MSAA FBO extension one where the texture is multisampled when bound to an FBO and
      * then implicitly resolved when read.
      */
     bool usesImplicitMSAAResolve() const {
         return kES_IMG_MsToTexture_MSFBOType == fMSFBOType ||
                kES_EXT_MsToTexture_MSFBOType == fMSFBOType;
     }
 
     InvalidateFBType invalidateFBType() const { return fInvalidateFBType; }
 
@@ skipping 171 matching lines @@
     bool fIsCoreProfile : 1;
     bool fBindFragDataLocationSupport : 1;
     bool fSRGBWriteControl : 1;
     bool fRGBA8888PixelsOpsAreSlow : 1;
     bool fPartialFBOReadIsSlow : 1;
     bool fBindUniformLocationSupport : 1;
     bool fExternalTextureSupport : 1;
     bool fRectangleTextureSupport : 1;
     bool fTextureSwizzleSupport : 1;
 
+    BlitFramebufferSupport fBlitFramebufferSupport;
+
     /** Number type of the components (with out considering number of bits.) */
     enum FormatType {
         kNormalizedFixedPoint_FormatType,
         kFloat_FormatType,
     };
 
     struct ReadPixelsFormat {
         ReadPixelsFormat() : fFormat(0), fType(0) {}
         GrGLenum fFormat;
         GrGLenum fType;
@@ skipping 54 matching lines @@
 
         GrSwizzle fSwizzle;
     };
 
     ConfigInfo fConfigTable[kGrPixelConfigCnt];
 
     typedef GrCaps INHERITED;
 };
 
 #endif