add PurgeResourceCache to track leaks

src/core/SkResourceCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChecksum.h"
 #include "SkResourceCache.h"
 #include "SkMipMap.h"
@@ skipping 285 matching lines @@
 #ifdef USE_HASH
     fHash->remove(rec->getKey());
 #endif
 
     SkDELETE(rec);
 
     fTotalBytesUsed -= used;
     fCount -= 1;
 }
 
-void SkResourceCache::purgeAsNeeded() {
+void SkResourceCache::purgeAsNeeded(bool forcePurge) {
     size_t byteLimit;
     int    countLimit;
 
     if (fDiscardableFactory) {
         countLimit = SK_DISCARDABLEMEMORY_SCALEDIMAGECACHE_COUNT_LIMIT;
         byteLimit = SK_MaxU32;  // no limit based on bytes
     } else {
         countLimit = SK_MaxS32; // no limit based on count
         byteLimit = fTotalByteLimit;
     }
 
     Rec* rec = fTail;
     while (rec) {
-        if (fTotalBytesUsed < byteLimit && fCount < countLimit) {
+        if (!forcePurge && fTotalBytesUsed < byteLimit && fCount < countLimit) {
             break;
         }
 
         Rec* prev = rec->fPrev;
         if (0 == rec->fLockCount) {
             this->remove(rec);
         }
         rec = prev;
     }
 }
@@ skipping 226 matching lines @@
 size_t SkResourceCache::SetSingleAllocationByteLimit(size_t size) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->setSingleAllocationByteLimit(size);
 }
 
 size_t SkResourceCache::GetSingleAllocationByteLimit() {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->getSingleAllocationByteLimit();
 }
 
+void SkResourceCache::PurgeAll() {
+    SkAutoMutexAcquire am(gMutex);
+    return get_cache()->purgeAll();
+}
+
 const SkResourceCache::Rec* SkResourceCache::FindAndLock(const Key& key) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->findAndLock(key);
 }
 
 const SkResourceCache::Rec* SkResourceCache::AddAndLock(Rec* rec) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->addAndLock(rec);
 }
 
@@ skipping 19 matching lines @@
 }
 
 size_t SkGraphics::GetResourceCacheSingleAllocationByteLimit() {
     return SkResourceCache::GetSingleAllocationByteLimit();
 }
 
 size_t SkGraphics::SetResourceCacheSingleAllocationByteLimit(size_t newLimit) {
     return SkResourceCache::SetSingleAllocationByteLimit(newLimit);
 }
 
+void SkGraphics::PurgeResourceCache() {
+    return SkResourceCache::PurgeAll();
+}
+