Revert of Refactor the loading tracking logic in WebContentsImpl.

Revert of Refactor the loading tracking logic in WebContentsImpl. (patchset #17 id:320001 of https://codereview.chromium.org/925623002/)

Reason for revert:
This patch causes the following layout tests' crashes:
- fast/loader/stateobjects/replacestate-in-onunload.html:

2921
2922      // This method should never be called when the frame is loading.
2923      DCHECK(!rfh->is_loading());
2924

#3  0x00007fffefece2d3 in content::WebContentsImpl::OnDidStartLoading (
    this=0x181e00571b20, to_different_document=false)
    at ../../content/browser/web_contents/web_contents_impl.cc:2923
#4  0x00007fffefefa3e7 in DispatchToMethodImpl<content::WebContentsImpl, void (content::WebContentsImpl::*)(bool), bool, 0ul> (obj=0x181e00571b20, method=
    (void (content::WebContentsImpl::*)(content::WebContentsImpl * const, bool)) 0x7fffefece170 <content::WebContentsImpl::OnDidStartLoading(bool)>, arg=...)
    at ../../base/tuple.h:246
#5  0x00007fffefefa335 in DispatchToMethod<content::WebContentsImpl, void (content::WebContentsImpl::*)(bool), bool> (obj=0x181e00571b20, method=
    (void (content::WebContentsImpl::*)(content::WebContentsImpl * const, bool)) 0x7fffefece170 <content::WebContentsImpl::OnDidStartLoading(bool)>, arg=...)
    at ../../base/tuple.h:253
#6  0x00007fffefee4bf7 in FrameHostMsg_DidStartLoading::Dispatch<content::WebContentsImpl, content::WebContentsImpl, void, void (content::WebContentsImpl::*)(bool)> (msg=0x181e006fddd0, obj=0x181e00571b20, sender=0x181e00571b20,
    parameter=0x0, func=

c.f. https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.7%20%28dbg%29/builds/19986

Original issue's description:
> Refactor the loading tracking logic in WebContentsImpl.
>
> This removes the loading_progresses_ map and the
> loading_frames_in_progress counter in WebContentsImpl.
> Instead, tracking of these is done at the RFHI level.
>
> BUG=429399
>
> Committed: https://crrev.com/bda82dd8f2286787212cb92c694a999f08834c7b
> Cr-Commit-Position: refs/heads/master@{#319267}

TBR=clamy@chromium.org,carlosk@chromium.org,nasko@chromium.org,creis@chromium.org,fdegans@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=429399
Committed: https://crrev.com/de32453de06c421e479ad5aa91ac07018c298d01
Cr-Commit-Position: refs/heads/master@{#319432}

[tasak, 2015-03-06 03:54:14]

Created Revert of Refactor the loading tracking logic in WebContentsImpl.

[commit-bot: I haz the power, 2015-03-06 03:54:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/983973002/1

[commit-bot: I haz the power, 2015-03-06 03:54:58]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-03-06 03:54:59]

Failed to apply patch for content/browser/frame_host/frame_tree_node.cc:
While running git apply --index -3 -p1;
  error: patch failed: content/browser/frame_host/frame_tree_node.cc:34
  Falling back to three-way merge...
  Applied patch to 'content/browser/frame_host/frame_tree_node.cc' with
conflicts.
  U content/browser/frame_host/frame_tree_node.cc

Patch:       content/browser/frame_host/frame_tree_node.cc
Index: content/browser/frame_host/frame_tree_node.cc
diff --git a/content/browser/frame_host/frame_tree_node.cc
b/content/browser/frame_host/frame_tree_node.cc
index
e3048ac8fa9405900f2f0286029e35dadf442e7a..845aecea62afc5945311f283f029c8d8b6504682
100644
--- a/content/browser/frame_host/frame_tree_node.cc
+++ b/content/browser/frame_host/frame_tree_node.cc
@@ -34,7 +34,8 @@
                       manager_delegate),
       frame_tree_node_id_(next_frame_tree_node_id_++),
       parent_(NULL),
-      replication_state_(name) {
+      replication_state_(name),
+      is_loading_(false) {
 }
 
 FrameTreeNode::~FrameTreeNode() {
@@ -114,26 +115,4 @@
   return false;
 }
 
-bool FrameTreeNode::IsLoading() const {
-  RenderFrameHostImpl* current_frame_host =
-      render_manager_.current_frame_host();
-  RenderFrameHostImpl* pending_frame_host =
-      render_manager_.pending_frame_host();
-
-  DCHECK(current_frame_host);
-  // TODO(fdegans): Change the implementation logic for PlzNavigate once
-  // DidStartLoading and DidStopLoading are properly called.
-  if (pending_frame_host && pending_frame_host->is_loading())
-    return true;
-  return current_frame_host->is_loading();
-}
-
-double FrameTreeNode::GetLoadingProgress() const {
-  RenderFrameHostImpl* current_frame_host =
-      render_manager_.current_frame_host();
-
-  DCHECK(current_frame_host);
-  return current_frame_host->loading_progress();
-}
-
 }  // namespace content

[commit-bot: I haz the power, 2015-03-06 03:55:06]

The CQ bit was unchecked by commit-bot@chromium.org

[tasak, 2015-03-06 10:38:45]

The CQ bit was checked by tasak@google.com

[commit-bot: I haz the power, 2015-03-06 10:39:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/983973002/90002

[commit-bot: I haz the power, 2015-03-06 10:40:00]

Committed patchset #2 (id:90002)

[commit-bot: I haz the power, 2015-03-06 10:40:49]

Patchset 2 (id:??) landed as
https://crrev.com/de32453de06c421e479ad5aa91ac07018c298d01
Cr-Commit-Position: refs/heads/master@{#319432}

[Fabrice (no longer in Chrome), 2015-03-06 15:15:53]

A revert of this CL (patchset #2 id:90002) has been created in
https://codereview.chromium.org/989473003/ by fdegans@chromium.org.

The reason for reverting is: Reland following
https://codereview.chromium.org/984983002/ landing in blink..