Revert of Eliminate kMojoChannelToken usage for render processes

Revert of Eliminate kMojoChannelToken usage for render processes (patchset #5 id:80001 of https://codereview.chromium.org/2201183005/ )

Reason for revert:
Needs rebase

Original issue's description:
> Eliminate kMojoChannelToken usage for render processes
> 
> Changes RenderProcessHostImpl to connect its IPC Channel
> by requesting a nominal IPC::mojom::ChannelBootstrap
> interface from its shell::Connection to the render process.
> 
> Changes ChildThreadImpl to support binding such requests
> by fusing them to its local IPC Channel if the (now deprecated)
> kMojoChannelToken was not provided.
> 
> BUG=623396
> R=ben@chromium.org
> 
> Committed: https://crrev.com/7a7f8f7e6977500d09270ff9d9b3817dda5e5b8a
> Cr-Commit-Position: refs/heads/master@{#410656}

TBR=ben@chromium.org,tsepez@chromium.org,jschuh@chromium.org,huangs@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=623396

[Ken Rockot(use gerrit already), 2016-08-09 14:21:18]

The CQ bit was checked by rockot@chromium.org

[Ken Rockot(use gerrit already), 2016-08-09 14:21:18]

Created Revert of Eliminate kMojoChannelToken usage for render processes

[commit-bot: I haz the power, 2016-08-09 14:21:44]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-09 14:22:13]

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

[commit-bot: I haz the power, 2016-08-09 14:22:14]

Failed to apply patch for content/browser/BUILD.gn:
While running git apply --index -3 -p1;
  error: patch failed: content/browser/BUILD.gn:71
  error: repository lacks the necessary blob to fall back on 3-way merge.
  error: content/browser/BUILD.gn: patch does not apply

Patch:       content/browser/BUILD.gn
Index: content/browser/BUILD.gn
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index
a2ab129d236e5ea12dc65bd249089caf1051457f..e0bc7d1ec6311cf06191245c28051fd67c40265b
100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -71,8 +71,6 @@
     "//gpu",
     "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/command_buffer/client:gles2_interface",
-    "//ipc",
-    "//ipc:mojom",
     "//media",
     "//media/capture",
     "//media/gpu/ipc/client",