Don't build the main executable binaries as Objective-C

Don't build the main executable binaries as Objective-C.

The operative portion of this change simply renames
chrome/app/chrome_exe_main_mac.mm to chrome/app/chrome_exe_main_mac.cc. The
main executables never used any Objective-C anyway. I named the files with .mm
a long time ago because at the time it meant that I didn't need to add a
separate GYP 'exclude' rule to keep other platforms from seeing the file. That
was before we added the rules to automatically exclude files based on platform
suffix like _mac.

This change also adds a "verify" step to the targets that build our main
executables. The verify step will cause a build failure if this ever
regresses.

This works around a bug in 10.5 CFBundlePreflightExecutable, which crashes
when called in a process whose main executable has slid due to PIE when the
main executable also contains an __OBJC,__image_info section. We enabled PIE
at r91243.

BUG=88697
TEST=No more crashes inside CFBundlePreflightExecutable (on our call from
     webkit::npapi::PluginLib::ReadWebPluginInfo) on 10.5
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=98122

[Scott Hess - ex-Googler, 2011-08-24 21:26:06]

LGTM.

http://codereview.chromium.org/7726007/diff/1/chrome/tools/build/mac/verify_n...
File chrome/tools/build/mac/verify_no_objc.sh (right):

http://codereview.chromium.org/7726007/diff/1/chrome/tools/build/mac/verify_n...
chrome/tools/build/mac/verify_no_objc.sh:32: if "${otool}" -arch i386 -o
"${executable}" | grep -q '^Contents.*section$'; \
On my 10.6 system, otool -o .../Google\ Chrome gives:

/Applications/Google Chrome.app/Contents/MacOS/Google Chrome:
Objective-C segment
can't print objective-C information no (__OBJC,__module_info) section

Whereas on 10.7 it gives:

Objective-C segment
Contents of (__OBJC,__image_info) section
  version 0
    flags 0x0

I _think_ this means that your test isn't testing what you want to test on 10.6?

[Mark Mentovai, 2011-08-24 21:34:36]

It works the same on 10.6 (Xcode 3.2.6 and 4.0) and 10.7 (Xcode 3.2.6 and 4.1)
for me. Can you tell me more about your Google Chrome binary? Your Xcode version
(xcodebuild -version)?

[Scott Hess - ex-Googler, 2011-08-24 21:47:37]

On Wed, Aug 24, 2011 at 2:34 PM,  <mark@chromium.org> wrote:
> It works the same on 10.6 (Xcode 3.2.6 and 4.0) and 10.7 (Xcode 3.2.6 and
> 4.1)
> for me. Can you tell me more about your Google Chrome binary? Your Xcode
> version
> (xcodebuild -version)?

My xcode looks old, 3.2.1.  Probably reasonable to not worry about
regression-catching that far into the past.

> http://codereview.chromium.org/7726007/

[TVL, 2011-08-25 13:43:27]

lgtm