Improvements/additions to SkImageCache/SkLazyPixelRef.

src/lazy/SkLruImageCache.cpp

Index: src/lazy/SkLruImageCache.cpp
diff --git a/src/lazy/SkLruImageCache.cpp b/src/lazy/SkLruImageCache.cpp
index 54f26fb5dcbf8263e143b12ce9efe846b5f1da38..160c16cf374e4ec7545133692189e0d2c01e95e1 100644
--- a/src/lazy/SkLruImageCache.cpp
+++ b/src/lazy/SkLruImageCache.cpp
@@ -74,16 +74,21 @@ SkLruImageCache::~SkLruImageCache() {
 }
 
 #ifdef SK_DEBUG
-SkImageCache::CacheStatus SkLruImageCache::getCacheStatus(intptr_t ID) const {
+SkImageCache::PinStatus SkLruImageCache::getPinStatus(intptr_t ID) const {
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
     if (NULL == pixels) {
-        return SkImageCache::kThrownAway_CacheStatus;
+        return SkImageCache::kThrownAway_PinStatus;
     }
     if (pixels->isLocked()) {
-        return SkImageCache::kPinned_CacheStatus;
+        return SkImageCache::kPinned_PinStatus;
     }
-    return SkImageCache::kUnpinned_CacheStatus;
+    return SkImageCache::kNeedsPin_PinStatus;
+}
+
+void SkLruImageCache::purgeAllCaches() {
+    SkAutoMutexAcquire ac(&fMutex);
+    this->purgeTilAtOrBelow(0);
 }
 #endif
 
@@ -108,7 +113,7 @@ void* SkLruImageCache::allocAndPinCache(size_t bytes, intptr_t* ID) {
     return pixels->getData();
 }
 
-void* SkLruImageCache::pinCache(intptr_t ID) {
+void* SkLruImageCache::pinCache(intptr_t ID, SkImageCache::PurgeStatus* status) {
     SkASSERT(ID != SkImageCache::UNINITIALIZED_ID);
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
@@ -119,6 +124,9 @@ void* SkLruImageCache::pinCache(intptr_t ID) {
         fLRU.remove(pixels);
         fLRU.addToHead(pixels);
     }
+    SkASSERT(status != NULL);
+    // This cache will never return pinned memory whose data has been overwritten.
+    *status = SkImageCache::kNotPurged_PurgeStatus;
     pixels->lock();
     return pixels->getData();
 }