rAc - do less work when model changes

The controller now does a lot more updating/clobbering/fiddling of the view when the model changes (i.e. all the stuff right after view_->ModelChanged()). This means we can afford to do a lot less in AutofillDialogViews::ModelChanged.

Although I'm not sure of the root cause of the crash in the bug, this will also have the side effect of fixing the crash because ModelChanged is part of the stack.

Also, as a further precaution, don't de-ref a possibly NULL |instrument| (even though it does seem like it should definitely be non-NULL).

BUG=343595

Review URL: https://codereview.chromium.org/164543002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251484 0039d316-1c4b-4281-b951-d872f2087c98
Disable Me2Me host controls on unsupported Linux systems.

Currently a system is considered to be supported in three cases:
 1. ~/.chrome-remote-desktop-session file exists.
 2. ~/.config/chrome-remote-desktop directory exists.
 3. DISTRIB_ID=Ubuntu is set in /etc/lsb-release

BUG=149744
R=lambroslambrou@chromium.org

Review URL: https://codereview.chromium.org/159753008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251485 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251484
Make code generated for histogram macros more compact.

In builds where DCHECKs are compiled in (e.g. developer
builds and Chrome Canaries), the DCHECK_EQ() in the
histogram macro was expanding to a lot of generated
machine code.

This CL moves that DCHECK() to a function instead, so that the
code is not duplicated in every call site. The function call is
wrapped behind a DCHECK_IS_ON() conditional, so that it will
still be omitted if DCHECKs are not compiled into the build.

Makes my Chromium release build smaller by over 1MB,
measuring size of Chromium Framework.

Before size: 146547380
After size:  145400692

BUG=343946
TEST=No functional changes.

Review URL: https://codereview.chromium.org/167343002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251486 0039d316-1c4b-4281-b951-d872f2087c98
[Hotword] Updating the helper extension to listen to the speech reset message from the main extension.

BUG=325439, 289023
TBR=jhawkins@chromium.org

Review URL: https://codereview.chromium.org/164313005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251487 0039d316-1c4b-4281-b951-d872f2087c98
Add a histogram "Download.FeedbackDialogEnabled"

This adds a new UMA histogram, "Download.FeedbackDialogEnabled." The histogram tells us how the user responded to the opt-in reporting dialog (enabled = true, disabled = false).

BUG=312533

Review URL: https://codereview.chromium.org/163433012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251488 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251488