Add MemoryCoordinatorClient

third_party/WebKit/Source/platform/MemoryCoordinator.cpp

Index: third_party/WebKit/Source/platform/MemoryCoordinator.cpp
diff --git a/third_party/WebKit/Source/core/dom/MemoryCoordinator.cpp b/third_party/WebKit/Source/platform/MemoryCoordinator.cpp
similarity index 53%
rename from third_party/WebKit/Source/core/dom/MemoryCoordinator.cpp
rename to third_party/WebKit/Source/platform/MemoryCoordinator.cpp
index 745d979f619014d132f3afd30088efb834717643..96fa073243f44e8c6af25ce2f388a258c1fd6eae 100644
--- a/third_party/WebKit/Source/core/dom/MemoryCoordinator.cpp
+++ b/third_party/WebKit/Source/platform/MemoryCoordinator.cpp
@@ -2,9 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "core/dom/MemoryCoordinator.h"
+#include "platform/MemoryCoordinator.h"
 
-#include "core/fetch/MemoryCache.h"
 #include "platform/TraceEvent.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/graphics/ImageDecodingStore.h"
@@ -13,6 +12,10 @@
 
 namespace blink {
 
+DEFINE_TRACE(MemoryCoordinatorClient)
+{
+}
+
 MemoryCoordinator& MemoryCoordinator::instance()
 {
     DEFINE_STATIC_LOCAL(MemoryCoordinator, instance, ());
@@ -27,17 +30,45 @@ MemoryCoordinator::~MemoryCoordinator()
 {
 }
 
+void MemoryCoordinator::registerClient(MemoryCoordinatorClient* client)
+{
+    DCHECK(isMainThread());
+    DCHECK(client);
+    DCHECK(!m_clients.contains(client));
+    m_clients.add(client);
+}
+
+void MemoryCoordinator::unregisterClient(MemoryCoordinatorClient* client)
+{
+    DCHECK(isMainThread());
+    m_clients.remove(client);
+}
+
+void MemoryCoordinator::purgeMemory()
+{
+    for (auto& client : m_clients)
+        client->purgeMemory();
+    WTF::Partitions::decommitFreeableMemory();
+}
+
 void MemoryCoordinator::onMemoryPressure(WebMemoryPressureLevel level)
 {
     TRACE_EVENT0("blink", "MemoryCoordinator::onMemoryPressure");
+    for (auto& client : m_clients)
+        client->onMemoryPressure(level);

[boliu, 2016/08/16 17:26:28]

Getting a null pointer crash here.
https://uberchromegw.corp.google.com/i/internal.client.clank/builders/health-...

	signal 11 (SIGSEGV), code 1, fault addr 0x1ba in tid 9575 (Chrome_InProcRe)
	pid: 9539, tid: 9575, name: Chrome_InProcRe  >>> org.chromium.webview_shell <<<
	signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x1ba
	     r0 2e49378c  r1 00000002  r2 2e364b90  r3 00000192
	     r4 a0020728  r5 b761ac38  r6 00000002  r7 a0020718
	     r8 a61955bc  r9 a617bdaa  sl b75d2ae4  fp a5c260b6
	     ip ffffff00  sp a00206e8  lr a4ed2399  pc a4ed23c6
	
	Stack Trace:
	  RELADDR   FUNCTION                                                           
       FILE:LINE
	  011ab3c6 
blink::MemoryCoordinator::onMemoryPressure(blink::WebMemoryPressureLevel) 
/b/build/slave/arm-builder-rel/build/src/third_party/WebKit/Source/platform/MemoryCoordinator.cpp:58

     if (level == WebMemoryPressureLevelCritical) {
         // Clear the image cache.
+        // TODO(tasak|bashi): Make ImageDecodingStore and FontCache be
+        // MemoryCoordinatorClients rather than clearing caches here.
         ImageDecodingStore::instance().clear();
         FontCache::fontCache()->invalidate();
     }
-    if (ProcessHeap::isLowEndDevice())
-        memoryCache()->pruneAll();
     WTF::Partitions::decommitFreeableMemory();
 }
 
+DEFINE_TRACE(MemoryCoordinator)
+{
+    visitor->trace(m_clients);
+}
+
 } // namespace blink