Make copySurface work for texture dsts, return a bool, & add unit test.

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 187a3ca37a7a1e416f83c0846c421c0ec49f3fe6..296dfb9e702736dab7e17bdf00f23d277f40e086 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -18,6 +18,7 @@
 #include "SkConfig8888.h"
 #include "SkGrPriv.h"
 
+#include "batches/GrCopySurfaceBatch.h"
 #include "effects/GrConfigConversionEffect.h"
 #include "text/GrTextBlobCache.h"
 
@@ -509,34 +510,42 @@ void GrContext::prepareSurfaceForExternalIO(GrSurface* surface) {
     }
 }
 
-void GrContext::copySurface(GrSurface* dst, GrSurface* src, const SkIRect& srcRect,
-                            const SkIPoint& dstPoint, uint32_t pixelOpsFlags) {
+bool GrContext::copySurface(GrSurface* dst, GrSurface* src, const SkIRect& srcRect,
+                            const SkIPoint& dstPoint) {
     ASSERT_SINGLE_OWNER
-    RETURN_IF_ABANDONED
+    RETURN_FALSE_IF_ABANDONED
     GR_AUDIT_TRAIL_AUTO_FRAME(&fAuditTrail, "GrContext::copySurface");
 
     if (!src || !dst) {
-        return;
+        return false;
     }
     ASSERT_OWNED_RESOURCE(src);
     ASSERT_OWNED_RESOURCE(dst);
 
-    // Since we're going to the draw target and not GPU, no need to check kNoFlush
-    // here.
     if (!dst->asRenderTarget()) {
-        return;
+        SkIRect clippedSrcRect;
+        SkIPoint clippedDstPoint;
+        if (!GrCopySurfaceBatch::ClipSrcRectAndDstPoint(dst, src, srcRect, dstPoint,
+                                                        &clippedSrcRect, &clippedDstPoint)) {
+            return false;
+        }
+        // If we don't have an RT for the dst then we won't have a GrDrawContext to insert the
+        // the copy surface into. In the future we plan to have a more limited Context type
+        // (GrCopyContext?) that has the subset of GrDrawContext operations that should be
+        // allowed on textures that aren't render targets.
+        // For now we just flush any writes to the src and issue an immediate copy to the dst.
+        src->flushWrites();
+        return fGpu->copySurface(dst, src, clippedSrcRect, clippedDstPoint);
     }
-
     SkAutoTUnref<GrDrawContext> drawContext(this->drawContext(dst->asRenderTarget()));
     if (!drawContext) {
-        return;
+        return false;
     }
 
-    drawContext->copySurface(src, srcRect, dstPoint);
-
-    if (kFlushWrites_PixelOp & pixelOpsFlags) {
-        this->flush();
+    if (!drawContext->copySurface(src, srcRect, dstPoint)) {
+        return false;
     }
+    return true;
 }
 
 void GrContext::flushSurfaceWrites(GrSurface* surface) {