Fix GPU displacement with expanding crop rects.

Fix GPU displacement with expanding crop rects, and re-enable the
imagefilterscropexpand GM. There were two bugs: the result texture was
being created at input color bitmap size, not the cropped bounds size,
and the matrix in GrContext was not being set to identity before draw.

R=junov@chromium.org

Review URL: https://codereview.chromium.org/195973007

git-svn-id: http://skia.googlecode.com/svn/trunk@13844 2bbb7eff-a529-9590-31e7-b0007b416f81

gyp/gmslides.gypi

@@ -101,8 +101,7 @@
     '../gm/imagefiltersbase.cpp',
     '../gm/imagefiltersclipped.cpp',
     '../gm/imagefilterscropped.cpp',
-# FIXME(senorblanco): re-enable once Win Debug failures are fixed
-#    '../gm/imagefilterscropexpand.cpp',
+    '../gm/imagefilterscropexpand.cpp',
     '../gm/imagefiltersgraph.cpp',
     '../gm/imagefiltersscaled.cpp',
     '../gm/internal_links.cpp',

src/effects/SkDisplacementMapEffect.cpp

@@ -384,8 +384,8 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
-    desc.fWidth = colorBM.width();
-    desc.fHeight = colorBM.height();
+    desc.fWidth = bounds.width();
+    desc.fHeight = bounds.height();
     desc.fConfig = kSkia8888_GrPixelConfig;
 
     GrAutoScratchTexture ast(context, desc);
@@ -410,6 +410,8 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
                                         color))->unref();
     SkIRect colorBounds = bounds;
     colorBounds.offset(-colorOffset);
+    GrContext::AutoMatrix am;
+    am.setIdentity(context);
     SkMatrix matrix;
     matrix.setTranslate(-SkIntToScalar(colorBounds.x()),
                         -SkIntToScalar(colorBounds.y()));