Adding blink gc memory dump infrastructure for thread specific dumps.

Source/platform/heap/BlinkGCMemoryDumpProvider.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "Source/platform/heap/BlinkGCMemoryDumpProvider.h"
 
 #include "platform/heap/Handle.h"
+#include "public/platform/Platform.h"
 #include "public/platform/WebMemoryAllocatorDump.h"
 #include "public/platform/WebProcessMemoryDump.h"
 #include "wtf/StdLibExtras.h"
 
 namespace blink {
 
 BlinkGCMemoryDumpProvider* BlinkGCMemoryDumpProvider::instance()
 {
     DEFINE_STATIC_LOCAL(BlinkGCMemoryDumpProvider, instance, ());
     return &instance;
 }
 
-bool BlinkGCMemoryDumpProvider::onMemoryDump(blink::WebProcessMemoryDump* memoryDump)
-{
-    WebMemoryAllocatorDump* allocatorDump = memoryDump->createMemoryAllocatorDump("blink_gc");
-    allocatorDump->AddScalar("inner_size", "bytes", Heap::allocatedObjectSize());
-    allocatorDump->AddScalar("outer_size", "bytes", Heap::allocatedSpace());
-    allocatorDump->AddScalar("estimated_live_object_size", "bytes", Heap::estimatedLiveObjectSize());
-    return true;
-}
-
-BlinkGCMemoryDumpProvider::BlinkGCMemoryDumpProvider()
-{
-}
-
 BlinkGCMemoryDumpProvider::~BlinkGCMemoryDumpProvider()
 {
 }
 
+bool BlinkGCMemoryDumpProvider::onMemoryDump(blink::WebProcessMemoryDump* memoryDump)
+{
+    m_currentProcessMemoryDump->clear();
+    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::TakeSnapshot, Heap::ForcedGC);

[Primiano Tucci (use gerrit), 2015/05/27 14:19:30]

Can you add a comment before this line clarifing that the collectGarbage will
create WMADs via createMemoryAllocatorDumpForCurrentGC in its call stack.

[ssid, 2015/05/27 14:39:33]

Added below.

+
+    WebMemoryAllocatorDump* allocatorDump = memoryDump->createMemoryAllocatorDump("blink_gc");
+    allocatorDump->AddScalar("inner_size", "bytes", Heap::allocatedObjectSize());
+    allocatorDump->AddScalar("outer_size", "bytes", Heap::allocatedSpace());
+    allocatorDump->AddScalar("estimated_live_object_size", "bytes", Heap::estimatedLiveObjectSize());
+
+    memoryDump->takeAllDumpsFrom(m_currentProcessMemoryDump.get());

[Primiano Tucci (use gerrit), 2015/05/27 14:19:30]

Or alternatively you can comment here saying:
merge all the dumps generated during the Heap::collectGarbage invocation

[ssid, 2015/05/27 14:39:33]

Done.

+    return true;
+}
+
+WebMemoryAllocatorDump* BlinkGCMemoryDumpProvider::createMemoryAllocatorDumpForCurrentGC(const String& absoluteName)
+{
+    return m_currentProcessMemoryDump->createMemoryAllocatorDump(absoluteName);
+}
+
+BlinkGCMemoryDumpProvider::BlinkGCMemoryDumpProvider()
+{
+    m_currentProcessMemoryDump = adoptPtr(Platform::current()->createProcessMemoryDump());

[Primiano Tucci (use gerrit), 2015/05/27 14:19:30]

Can you do this in the ctor initializer list? Otherwise I wonder if the clang
checked will falsely barf about m_currentProcessMemoryDump being not
initialized.

[ssid, 2015/05/27 14:39:33]

Done.

+    ASSERT(m_currentProcessMemoryDump);
+}
+
 } // namespace blink