NavigationTiming: set navigationStart for navigations in new tabs.

content/common/frame_messages.h

 // Copyright 2013 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.
 
 // IPC messages for interacting with frames.
 // Multiply-included message file, hence no include guard.
 
 #include "content/common/content_export.h"
 #include "content/common/content_param_traits.h"
 #include "content/common/frame_message_enums.h"
@@ skipping 191 matching lines @@
   // history entry when it commits. This is used for cross-process redirects so
   // the transferred navigation can recover the navigation state.
   IPC_STRUCT_MEMBER(bool, should_replace_current_entry)
 
   // Opaque history state (received by ViewHostMsg_UpdateState).
   IPC_STRUCT_MEMBER(content::PageState, page_state)
 
   // Type of navigation.
   IPC_STRUCT_MEMBER(FrameMsg_Navigate_Type::Value, navigation_type)
 
-  // The time the request was created
+  // The time the request was created. This is used by the old performance
+  // infrastructure to set up DocumentState associated with the RenderView.
+  // TODO(ppi): make it go away.
   IPC_STRUCT_MEMBER(base::Time, request_time)
 
   // Extra headers (separated by \n) to send during the request.
   IPC_STRUCT_MEMBER(std::string, extra_headers)
 
   // The following two members identify a previous request that has been
   // created before this navigation is being transferred to a new render view.
   // This serves the purpose of recycling the old request.
   // Unless this refers to a transferred navigation, these values are -1 and -1.
   IPC_STRUCT_MEMBER(int, transferred_request_child_id)
@@ skipping 12 matching lines @@
   // otherwise.
   IPC_STRUCT_MEMBER(std::vector<unsigned char>, browser_initiated_post_data)
 
   // Whether or not this url should be allowed to access local file://
   // resources.
   IPC_STRUCT_MEMBER(bool, can_load_local_resources)
 
   // If not empty, which frame to navigate.
   IPC_STRUCT_MEMBER(std::string, frame_to_navigate)
 
-  // The navigationStart time to expose to JS for this navigation.
+  // The navigationStart time to expose through the Navigation Timing API to JS.
   IPC_STRUCT_MEMBER(base::TimeTicks, browser_navigation_start)
 IPC_STRUCT_END()
 
 IPC_STRUCT_BEGIN(FrameHostMsg_OpenURL_Params)
   IPC_STRUCT_MEMBER(GURL, url)
   IPC_STRUCT_MEMBER(content::Referrer, referrer)
   IPC_STRUCT_MEMBER(WindowOpenDisposition, disposition)
   IPC_STRUCT_MEMBER(bool, should_replace_current_entry)
   IPC_STRUCT_MEMBER(bool, user_gesture)
 IPC_STRUCT_END()
@@ skipping 353 matching lines @@
 // |endOffset| are the offsets of the selection in the returned |content|.
 IPC_MESSAGE_ROUTED3(FrameHostMsg_TextSurroundingSelectionResponse,
                     base::string16,  /* content */
                     size_t, /* startOffset */
                     size_t /* endOffset */)
 
 // Notifies the browser that the renderer has a pending navigation transition.
 IPC_MESSAGE_CONTROL2(FrameHostMsg_SetHasPendingTransitionRequest,
                      int /* render_frame_id */,
                      bool /* is_transition */)