Implement frame attribution (FrameBlamer)

content/renderer/render_frame_blame_context.cc

+// Copyright 2016 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/renderer/render_frame_blame_context.h"
+
+#include "base/trace_event/trace_event_argument.h"
+#include "content/renderer/render_frame_impl.h"
+#include "content/renderer/render_thread_blame_context.h"
+#include "content/renderer/render_thread_impl.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+
+namespace content {
+namespace {
+
+base::trace_event::BlameContext* GetParentBlameContext(
+    RenderFrame* render_frame) {
+  blink::WebLocalFrame* web_frame = render_frame->GetWebFrame();
+  if (web_frame->parent()) {
+    return RenderFrameImpl::FromWebFrame(web_frame->parent())
+        ->frameBlameContext();
+  }
+  return RenderThreadImpl::current()->blame_context();
+}
+
+}  // namespace
+
+const char kRenderFrameBlameContextCategory[] = "blink";
+const char kRenderFrameBlameContextName[] = "FrameBlameContext";
+const char kRenderFrameBlameContextType[] = "RenderFrame";
+const char kRenderFrameBlameContextScope[] = "RenderFrame";
+
+RenderFrameBlameContext::RenderFrameBlameContext(RenderFrameImpl* render_frame)
+    : base::trace_event::BlameContext(kRenderFrameBlameContextCategory,
+                                      kRenderFrameBlameContextName,
+                                      kRenderFrameBlameContextType,
+                                      kRenderFrameBlameContextScope,
+                                      render_frame->GetRoutingID(),
+                                      GetParentBlameContext(render_frame)),
+      RenderFrameObserver(render_frame) {}
+
+RenderFrameBlameContext::~RenderFrameBlameContext() {}
+
+void RenderFrameBlameContext::DidCreateNewDocument() {
+  url_ = render_frame()->GetWebFrame()->getSecurityOrigin().toString().utf8();

[esprehn, 2016/03/25 03:33:22]

ouch, this is putting even more code in content. I'd rather we didn't do this.
Why is this not an API of blink?

+  TakeSnapshot();
+}
+
+void RenderFrameBlameContext::AsValueInto(
+    base::trace_event::TracedValue* state) {
+  base::trace_event::BlameContext::AsValueInto(state);
+  state->SetString("url", url_);

[esprehn, 2016/03/25 03:33:22]

yeah this doesn't belong in content.

+}
+
+}  // namespace content