Use approximate scratch textures for image filters.

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrBicubicEffect.h"
@@ skipping 1745 matching lines @@
     desc.fFlags = kRenderTarget_GrTextureFlagBit;
     desc.fWidth = info.width();
     desc.fHeight = info.height();
     desc.fSampleCnt = fRenderTarget->numSamples();
 
     SkAutoTUnref<GrTexture> texture;
     // Skia's convention is to only clear a device if it is non-opaque.
     unsigned flags = info.isOpaque() ? 0 : kNeedClear_Flag;
 
 #if CACHE_COMPATIBLE_DEVICE_TEXTURES
-    // layers are never draw in repeat modes, so we can request an approx
-    // match and ignore any padding.
-    const GrContext::ScratchTexMatch match = (kSaveLayer_Usage == usage) ?
-                                                GrContext::kApprox_ScratchTexMatch :
-                                                GrContext::kExact_ScratchTexMatch;
+    // layers are never draw in repeat modes or with mip maps, so we can request an approx
+    // match and ignore any padding. Image filters (at present) don't tile their inputs or use mip
+    // maps, either.
+    const GrContext::ScratchTexMatch match =
+        (kSaveLayer_Usage == usage || kImageFilter_Usage == usage) ?
+            GrContext::kApprox_ScratchTexMatch :
+            GrContext::kExact_ScratchTexMatch;
     texture.reset(fContext->refScratchTexture(desc, match));
 #else
     texture.reset(fContext->createUncachedTexture(desc, NULL, 0));
 #endif
     if (texture.get()) {
         return SkGpuDevice::Create(texture, SkSurfaceProps(SkSurfaceProps::kLegacyFontHost_InitType), flags);
     } else {
         GrPrintf("---- failed to create compatible device texture [%d %d]\n",
                  info.width(), info.height());
         return NULL;
@@ skipping 54 matching lines @@
     GrLayerHoister::UnlockLayers(fContext, atlased, nonAtlased, recycled);
 
     return true;
 }
 
 SkImageFilter::Cache* SkGpuDevice::getImageFilterCache() {
     // We always return a transient cache, so it is freed after each
     // filter traversal.
     return SkImageFilter::Cache::Create(kDefaultImageFilterCacheSize);
 }