Rename Chrome threads to use a "Cr" prefix.

Rename Chrome threads to use a "Cr" prefix. 

Before we carefully used the app (Chrome/Chromium) name, but:
1) these are for internal debugging use only, so why compute this name
2) on Linux the thread ids are limited to 16 characters, and "Chromium"
   is too long

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=49296

[Evan Martin, 2010-06-08 23:06:00]

M-A wrote the original patch that introduced putting "Chrome_" in our thread
names back in 2007.  It appears since then everyone has just copied that pattern
(including making it abstract for Chrome vs Chromium) ever since.

Is there a reason for it?  I'd like to remove it.

[scherkus (not reviewing), 2010-06-08 23:09:37]

What about threads created + named via base::Thread() constructor?

base/thread.cc calls PlatformThread::SetName() with the thread name untouched
(i.e., doesn't prefix Cr)

[Evan Martin, 2010-06-08 23:12:02]

On 2010/06/08 23:09:37, scherkus wrote:
> What about threads created + named via base::Thread() constructor?
> 
> base/thread.cc calls PlatformThread::SetName() with the thread name untouched
> (i.e., doesn't prefix Cr)

I'd be happy to remove the prefix altogether, but I figured there was probably
some reason for it.  (Like, say, the Chrome threads all alphabetize together,
maybe?)

[Avi (use Gerrit), 2010-06-08 23:13:18]

http://codereview.chromium.org/2741003/diff/1/9
File chrome/utility/utility_main.cc (right):

http://codereview.chromium.org/2741003/diff/1/9#newcode28
chrome/utility/utility_main.cc:28: std::wstring app_name =
chrome::kBrowserAppName;
kill app_name too?

[Avi (use Gerrit), 2010-06-08 23:14:09]

On 2010/06/08 23:12:02, Evan Martin wrote:
> I figured there was probably
> some reason for it.  (Like, say, the Chrome threads all alphabetize together,
> maybe?)

Or perhaps to distinguish the threads we create from the ones that are created
on our behalf by the OS.

[Evan Martin, 2010-06-08 23:21:32]

(Since there are more commenters on this now, I'll note I have another patch
almost ready to go that makes the thread-name setting work on Linux and Mac;
Xcode 3.2 will reportedly show them in the debugger.)

[M-A Ruel, 2010-06-09 01:32:30]

lgtm with nit

http://codereview.chromium.org/2741003/diff/1/2
File chrome/browser/browser_main.cc (right):

http://codereview.chromium.org/2741003/diff/1/2#newcode826
chrome/browser/browser_main.cc:826: const char kThreadName[] = "CrBrowserMain";
No, you create an array on the stack, very very sad.
const char* kThreadName = "CrBrowserMain";
(the second const is optional in this case)

[Nicolas Sylvain, 2010-06-09 14:07:57]

LGTM with the comments from others.

The try job on windows is red a lot. Please make sure there is not something in
the ui tests that relies on the thread name to synchronize.