Fix layer hoisting image filter corner cases

src/gpu/GrLayerCache.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAtlas.h"
 #include "GrGpu.h"
 #include "GrLayerCache.h"
@@ skipping 105 matching lines @@
         SkDELETE(layer);
     }
     fLayerHash.rewind();
 
     // The atlas only lets go of its texture when the atlas is deleted.
     fAtlas.free();
 }
 
 GrCachedLayer* GrLayerCache::createLayer(uint32_t pictureID,
                                          int start, int stop,
-                                         const SkIRect& bounds,
+                                         const SkIRect& srcIR,
+                                         const SkIRect& dstIR,
                                          const SkMatrix& initialMat,
                                          const unsigned* key,
                                          int keySize,
                                          const SkPaint* paint) {
     SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);
 
-    GrCachedLayer* layer = SkNEW_ARGS(GrCachedLayer, (pictureID, start, stop, bounds, initialMat,
+    GrCachedLayer* layer = SkNEW_ARGS(GrCachedLayer, (pictureID, start, stop,
+                                                      srcIR, dstIR, initialMat,
                                                       key, keySize, paint));
     fLayerHash.add(layer);
     return layer;
 }
 
 GrCachedLayer* GrLayerCache::findLayer(uint32_t pictureID, const SkMatrix& initialMat,
                                        const unsigned* key, int keySize) {
     SkASSERT(pictureID != SK_InvalidGenID);
     return fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
 }
 
 GrCachedLayer* GrLayerCache::findLayerOrCreate(uint32_t pictureID,
                                                int start, int stop,
-                                               const SkIRect& bounds,
+                                               const SkIRect& srcIR,
+                                               const SkIRect& dstIR,
                                                const SkMatrix& initialMat,
                                                const unsigned* key,
                                                int keySize,
                                                const SkPaint* paint) {
     SkASSERT(pictureID != SK_InvalidGenID && start >= 0 && stop > 0);
     GrCachedLayer* layer = fLayerHash.find(GrCachedLayer::Key(pictureID, initialMat, key, keySize));
     if (NULL == layer) {
-        layer = this->createLayer(pictureID, start, stop, bounds, initialMat, key, keySize, paint);
+        layer = this->createLayer(pictureID, start, stop,
+                                  srcIR, dstIR, initialMat,
+                                  key, keySize, paint);
     }
 
     return layer;
 }
 
 bool GrLayerCache::tryToAtlas(GrCachedLayer* layer,
                               const GrSurfaceDesc& desc,
                               bool* needsRendering) {
     SkDEBUGCODE(GrAutoValidateLayer avl(fAtlas ? fAtlas->getTexture() : NULL, layer);)
 
@@ skipping 69 matching lines @@
     return false;
 }
 
 bool GrLayerCache::lock(GrCachedLayer* layer, const GrSurfaceDesc& desc, bool* needsRendering) {
     if (layer->locked()) {
         // This layer is already locked
         *needsRendering = false;
         return true;
     }
 
+    // TODO: make the test for exact match depend on the image filters themselves
+    GrContext::ScratchTexMatch usage = GrContext::kApprox_ScratchTexMatch;
+    if (layer->fFilter) {
+        usage = GrContext::kExact_ScratchTexMatch;
+    }
+
     SkAutoTUnref<GrTexture> tex(
-        fContext->refScratchTexture(desc, GrContext::kApprox_ScratchTexMatch));
+        fContext->refScratchTexture(desc, usage));
 
     if (!tex) {
         return false;
     }
 
     layer->setTexture(tex, SkIRect::MakeWH(desc.fWidth, desc.fHeight));
     layer->setLocked(true);
     *needsRendering = true;
     return true;
 }
@@ skipping 237 matching lines @@
         fileName.appendf("\\%d", layer->fKey.pictureID());
         for (int i = 0; i < layer->fKey.keySize(); ++i) {
             fileName.appendf("-%d", layer->fKey.key()[i]);
         }
         fileName.appendf(".png");
 
         layer->texture()->surfacePriv().savePixels(fileName.c_str());
     }
 }
 #endif