Add MemoryCoordinatorClient

third_party/WebKit/Source/core/fetch/MemoryCache.cpp

Index: third_party/WebKit/Source/core/fetch/MemoryCache.cpp
diff --git a/third_party/WebKit/Source/core/fetch/MemoryCache.cpp b/third_party/WebKit/Source/core/fetch/MemoryCache.cpp
index 68ef8fef863a9123f082c245181795fc41f5b831..2aba9aaad3e26eea531f3d556da2bd0875edee7e 100644
--- a/third_party/WebKit/Source/core/fetch/MemoryCache.cpp
+++ b/third_party/WebKit/Source/core/fetch/MemoryCache.cpp
@@ -104,6 +104,7 @@ inline MemoryCache::MemoryCache()
 #endif
 {
     MemoryCacheDumpProvider::instance()->setMemoryCache(this);
+    MemoryCoordinator::instance().registerClient(this);
 #ifdef MEMORY_CACHE_STATS
     const double statsIntervalInSeconds = 15;
     m_statsTimer.startRepeating(statsIntervalInSeconds, BLINK_FROM_HERE);
@@ -119,6 +120,7 @@ MemoryCache::~MemoryCache()
 {
     if (m_prunePending)
         Platform::current()->currentThread()->removeTaskObserver(this);
+    MemoryCoordinator::instance().unregisterClient(this);

[haraken, 2016/08/12 02:55:00]

We don't need to call this since the client is automatically removed by Oilpan's
weak processing.

[bashi, 2016/08/16 00:09:06]

Removed.

Does it mean we should have null checks in MemoryCoordinator when it iterates
over |m_clients|?

[haraken, 2016/08/16 02:37:04]

No. Cleared entries are automatically removed from the HashSet by Oilpan, so you
don't need to worry about it. (Also it's guaranteed that Oilpan doesn't collect
the objects while someone is iterating the HashSet on the stack.)

[bashi, 2016/08/16 02:39:41]

I see. Thanks for clarification.

 }
 
 DEFINE_TRACE(MemoryCache)
@@ -127,6 +129,7 @@ DEFINE_TRACE(MemoryCache)
     visitor->trace(m_liveDecodedResources);
     visitor->trace(m_resourceMaps);
     MemoryCacheDumpClient::trace(visitor);
+    MemoryCoordinatorClient::trace(visitor);
 }
 
 KURL MemoryCache::removeFragmentIdentifierIfNeeded(const KURL& originalURL)
@@ -735,6 +738,12 @@ bool MemoryCache::onMemoryDump(WebMemoryDumpLevelOfDetail levelOfDetail, WebProc
     return true;
 }
 
+void MemoryCache::onMemoryPressure(WebMemoryPressureLevel level)
+{
+    if (ProcessHeap::isLowEndDevice())

[esprehn, 2016/08/15 15:41:07]

Hmm, should we do this in the constructor then? Calling this method and having
it be a no-op seems strange.

[bashi, 2016/08/16 00:09:06]

Done.

tasak@: you might want to move back this condition when you implement
purgeMemory() interface in MemoryCache.

+        pruneAll();
+}
+
 bool MemoryCache::isInSameLRUListForTest(const Resource* x, const Resource* y)
 {
     MemoryCacheEntry* ex = getEntryForResource(x);