More Compiler.h cleanups.

More Compiler.h cleanups.

* We support neither gcce nor icc.
* Our gcc is always newer than 3.0.3.
* Our clang always has __has_extension
* UNUSED_LABEL isn't used anywhere

BUG=none

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=150429

[abarth-chromium, 2013-05-15 02:43:08]

lgtm

[commit-bot: I haz the power, 2013-05-15 02:44:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/14734009/1005

[commit-bot: I haz the power, 2013-05-15 02:44:31]

Failed to apply patch for Source/wtf/Assertions.h:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file Source/wtf/Assertions.h
  Hunk #1 succeeded at 225 (offset 27 lines).
  Hunk #2 FAILED at 263.
  1 out of 2 hunks FAILED -- saving rejects to file Source/wtf/Assertions.h.rej

Patch:       Source/wtf/Assertions.h
Index: Source/wtf/Assertions.h
diff --git a/Source/wtf/Assertions.h b/Source/wtf/Assertions.h
index
7e52890cc5588190824040d9f019878aedb0946f..7fec4d933a9475de8e3491b2ae519c07c2dc5b3d
100644
--- a/Source/wtf/Assertions.h
+++ b/Source/wtf/Assertions.h
@@ -198,13 +198,7 @@ void WTFInstallReportBacktraceOnCrashHook();
 #define ASSERT_NOT_REACHED() ((void)0)
 #define NO_RETURN_DUE_TO_ASSERT
 
-#if COMPILER(INTEL) && !OS(WINDOWS)
-template<typename T>
-inline void assertUnused(T& x) { (void)x; }
-#define ASSERT_UNUSED(variable, assertion) (assertUnused(variable))
-#else
 #define ASSERT_UNUSED(variable, assertion) ((void)variable)
-#endif
 
 #else
 
@@ -269,13 +263,7 @@ while (0)
 /* ASSERT_WITH_MESSAGE_UNUSED */
 
 #if ASSERT_MSG_DISABLED
-#if COMPILER(INTEL) && !OS(WINDOWS)
-template<typename T>
-inline void assertWithMessageUnused(T& x) { (void)x; }
-#define ASSERT_WITH_MESSAGE_UNUSED(variable, assertion, ...)
(assertWithMessageUnused(variable))
-#else
 #define ASSERT_WITH_MESSAGE_UNUSED(variable, assertion, ...) ((void)variable)
-#endif
 #else
 #define ASSERT_WITH_MESSAGE_UNUSED(variable, assertion, ...) do \
     if (!(assertion)) { \

[commit-bot: I haz the power, 2013-05-15 05:45:37]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/14734009/6001

[commit-bot: I haz the power, 2013-05-15 14:38:38]

Change committed as 150429