Every pixel ref gets its own mutex.

src/gpu/SkGrPixelRef.cpp

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #include "SkGrPixelRef.h"
 
 #include "GrContext.h"
 #include "GrTexture.h"
 #include "GrTexturePriv.h"
 #include "SkBitmapCache.h"
 #include "SkGr.h"
 #include "SkRect.h"
 
-// since we call lockPixels recursively on fBitmap, we need a distinct mutex,
-// to avoid deadlock with the default one provided by SkPixelRef.
-SK_DECLARE_STATIC_MUTEX(gROLockPixelsPixelRefMutex);
-
 SkROLockPixelsPixelRef::SkROLockPixelsPixelRef(const SkImageInfo& info)
-    : INHERITED(info, &gROLockPixelsPixelRefMutex) {}
+    : INHERITED(info) {}
 
 SkROLockPixelsPixelRef::~SkROLockPixelsPixelRef() {}
 
 bool SkROLockPixelsPixelRef::onNewLockPixels(LockRec* rec) {
     fBitmap.reset();
 //    SkDebugf("---------- calling readpixels in support of lockpixels\n");
     if (!this->onReadPixels(&fBitmap, NULL)) {
         SkDebugf("SkROLockPixelsPixelRef::onLockPixels failed!\n");
         return false;
     }
@@ skipping 48 matching lines @@
     GrTexture* dst = context->textureProvider()->createTexture(desc, false, NULL, 0);
     if (NULL == dst) {
         return NULL;
     }
 
     // Blink is relying on the above copy being sent to GL immediately in the case when the source
     // is a WebGL canvas backing store. We could have a TODO to remove this flush flag, but we have
     // a larger TODO to remove SkGrPixelRef entirely.
     context->copySurface(dst->asRenderTarget(), texture, srcRect, SkIPoint::Make(0,0),
                          GrContext::kFlushWrites_PixelOp);
-  
+
     SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, dstCT, kPremul_SkAlphaType,
                                          dstPT);
     SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
     SkSafeUnref(dst);
     return pixelRef;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkGrPixelRef::SkGrPixelRef(const SkImageInfo& info, GrSurface* surface) : INHERITED(info) {
@@ skipping 93 matching lines @@
         cachedBitmap.setImmutable();
         //Add to the cache
         SkBitmapCache::Add(this, bounds, cachedBitmap);
 
         dst->swap(cachedBitmap);
     }
 
     return true;
 
 }