Revert 195379 "roll clang 176256:179138"

Numerous CrOS test failures: see http://crbug.com/234010

> roll clang 176256:179138
> 
> BUG=233709
> TBR=hans
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=195220
> 
> Review URL: https://chromiumcodereview.appspot.com/14169006

TBR=thakis@chromium.org
BUG=234010

Review URL: https://codereview.chromium.org/13871019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195429 0039d316-1c4b-4281-b951-d872f2087c98

build/common.gypi

@@ -2969,13 +2969,6 @@
               '-Xclang', '-add-plugin', '-Xclang', '<(clang_add_plugin)',
             ],
           }],
-          ['clang==1 and target_arch=="ia32"', {
-            'cflags': [
-              # Else building libyuv gives clang's register allocator issues,
-              # see llvm.org/PR15798 / crbug.com/233709
-              '-momit-leaf-frame-pointer',
-            ],
-          }],
           ['clang==1 and "<(GENERATOR)"=="ninja"', {
             'cflags': [
               # See http://crbug.com/110262

tools/clang/scripts/update.sh

@@ -8,7 +8,7 @@
 # Do NOT CHANGE this if you don't know what you're doing -- see
 # https://code.google.com/p/chromium/wiki/UpdatingClang
 # Reverting problematic clang rolls is safe, though.
-CLANG_REVISION=179138
+CLANG_REVISION=176256
 # ASan Mac builders are pinned to this revision, see http://crbug.com/170629.
 CLANG_ASAN_MAC_REVISION=170392