Implement GetSkiaTraceMemoryDump and AddSuballocation on chrome blink platform impl

content/child/web_process_memory_dump_impl.cc

 // 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 "content/child/web_process_memory_dump_impl.h"
 
 #include "base/trace_event/process_memory_dump.h"
 #include "content/child/web_memory_allocator_dump_impl.h"
+#include "skia/ext/SkTraceMemoryDump_chrome.h"

[ssid, 2015/09/04 08:54:00]

Also, deps addition is not required, it is already added in parent directory
DEPS :)

 
 namespace content {
 
 WebProcessMemoryDumpImpl::WebProcessMemoryDumpImpl()
     : owned_process_memory_dump_(
           new base::trace_event::ProcessMemoryDump(nullptr)),
       process_memory_dump_(owned_process_memory_dump_.get()) {
 }
 
 WebProcessMemoryDumpImpl::WebProcessMemoryDumpImpl(
@@ skipping 106 matching lines @@
 }
 
 void WebProcessMemoryDumpImpl::AddOwnershipEdge(
     blink::WebMemoryAllocatorDumpGuid source,
     blink::WebMemoryAllocatorDumpGuid target) {
   process_memory_dump_->AddOwnershipEdge(
       base::trace_event::MemoryAllocatorDumpGuid(source),
       base::trace_event::MemoryAllocatorDumpGuid(target));
 }
 
+SkTraceMemoryDump* WebProcessMemoryDumpImpl::CreateSkiaTraceMemoryDump(
+    const blink::WebString& dumpNamePrefix) {
+  sk_trace_dump_.reset(new skia::SkTraceMemoryDump_Chrome(

[Primiano Tucci (use gerrit), 2015/09/04 10:02:16]

Hmm if you store it into a scoped_ptr implies that you can create only one
adapter (with one prefix) at all for each dump. Isn't this a bit limiting? 
I think the options here are:
 A. You keep the memory ownership of the skia wrappers here, but make
sk_trace_Dump a ScopedVector instead.

 B. You move the memory ownership of this to the caller (so return a naked
pointer) and the caller has the responsibility of owning and destroying properly
the wrapper.

I'd go for A as, IIRC, the skia wrapper cannot outlive the process memory dump.
BUt please document that in the comment of Create... method.

[ssid, 2015/09/07 17:29:53]

Done.

+      dumpNamePrefix.utf8().data(), process_memory_dump_));
+  return sk_trace_dump_.get();
+}
+
 }  // namespace content