Adding blink gc memory dump infrastructure for thread specific dumps.

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index c938b3a3ffe05e998fc64b37b3048150329650cc..3b5575e96dbc6dc2cf7708fa1c22568d6c16a1ad 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -41,6 +41,8 @@
 #include "platform/heap/SafePoint.h"
 #include "platform/heap/ThreadState.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebMemoryAllocatorDump.h"
+#include "public/platform/WebProcessMemoryDump.h"
 #include "wtf/Assertions.h"
 #include "wtf/ContainerAnnotations.h"
 #include "wtf/LeakAnnotations.h"
@@ -213,6 +215,21 @@ void BaseHeap::cleanupPages()
     m_firstPage = nullptr;
 }
 
+void BaseHeap::dumpMemoryInto(WebProcessMemoryDump* memoryDump, const char* heapName)
+{
+    String dumpName;
+    if (threadState()->isMainThread()) {
+        dumpName = String::format("blink_gc/thread_main/heaps/%s", heapName);
+    } else {
+        dumpName = String::format("blink_gc/thread_%ld/heaps/%s", currentThread(), heapName);
+    }
+    WebMemoryAllocatorDump* allocatorDump = memoryDump->createMemoryAllocatorDump(dumpName);
+
+    size_t pageCount = 0;
+    for (BasePage* page = m_firstPage; page; page = page->next(), ++pageCount) { }

[petrcermak, 2015/05/21 13:15:57]

I would personally put the increment in the body of the loop:

for (BasePage* page = m_firstPage; page; page = page->next()) {
  ++pageCount;
}

I think it makes the code more readable.

[picksi, 2015/05/21 15:33:49]

+1 

[ssid, 2015/05/21 16:55:28]

Done.

+    allocatorDump->AddScalar("blink_page_count", "objects", pageCount);

[petrcermak, 2015/05/21 13:15:57]

The only alternative I can think of is "base_page_count" (because it's the
BasePage class), but I think "blink_page_count" sounds fine (long name is better
than ambiguous name).

[ssid, 2015/05/21 16:55:28]

Acknowledged.

+}
+
 #if ENABLE(ASSERT) || ENABLE(GC_PROFILING)
 BasePage* BaseHeap::findPageFromAddress(Address address)
 {