Make it possible to build webrtc for arm64.

- Bump revision of protobuf lib
- Remove -Wextra for arm64 gcc targets (warnings in stlport)
- Add MemoryBarrier implementation in single_rw_fifo.cc.
- [pending 15619004]: Bump revision of /deps/tools/android to get md5sum_bin for arm64.

BUG=chromium:354405,chromium:354539
R=andrew@webrtc.org, fischman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/15629004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6330 4adac7df-926f-26a2-2b94-8c16560cd09d

DEPS

@@ -108,7 +108,7 @@ deps = {
     Var("chromium_trunk") + "/deps/third_party/opus@256783",
 
   "third_party/protobuf":
-    Var("chromium_trunk") + "/src/third_party/protobuf@251211",
+    Var("chromium_trunk") + "/src/third_party/protobuf@" + Var("chromium_revision"),
 
   "third_party/sqlite/":
     Var("chromium_trunk") + "/src/third_party/sqlite@" + Var("chromium_revision"),
@@ -205,7 +205,7 @@ deps_os = {
     # Precompiled tools needed for Android test execution. Needed since we can't
     # compile them from source in WebRTC since they depend on Chromium's base.
     "tools/android":
-      (Var("googlecode_url") % "webrtc") + "/deps/tools/android@4258",
+      (Var("googlecode_url") % "webrtc") + "/deps/tools/android@6306",
 
     "third_party/android_tools":
       From("chromium_deps", "src/third_party/android_tools"),

webrtc/build/common.gypi

@@ -189,13 +189,23 @@
       }, {
         'conditions': [
           ['os_posix==1', {
-            'cflags': [
+            'conditions': [
-              '-Wextra',
+              # -Wextra is currently disabled in Chromium's common.gypi. Enable
-              # We need to repeat some flags from Chromium's common.gypi here
+              # for targets that can handle it. For Android/arm64 right now
-              # that get overridden by -Wextra.
+              # there will be an 'enumeral and non-enumeral type in conditional
-              '-Wno-unused-parameter',
+              # expression' warning in android_tools/ndk_experimental's version
-              '-Wno-missing-field-initializers',
+              # of stlport.
-              '-Wno-strict-overflow',
+              # See: https://code.google.com/p/chromium/issues/detail?id=379699
+              ['target_arch!="arm64" or OS!="android"', {
+                'cflags': [
+                  '-Wextra',
+                  # We need to repeat some flags from Chromium's common.gypi
+                  # here that get overridden by -Wextra.
+                  '-Wno-unused-parameter',
+                  '-Wno-missing-field-initializers',
+                  '-Wno-strict-overflow',
+                ],
+              }],
             ],
             'cflags_cc': [
               '-Wnon-virtual-dtor',

webrtc/modules/audio_device/android/single_rw_fifo.cc

@@ -20,14 +20,16 @@ namespace webrtc {
 
 namespace subtle {
 
-#if defined(__ARMEL__)
+#if defined(__aarch64__)
-// From http://src.chromium.org/viewvc/chrome/trunk/src/base/atomicops_internals_arm_gcc.h
+// From http://http://src.chromium.org/viewvc/chrome/trunk/src/base/atomicops_internals_arm64_gcc.h
-// Note that it is only the MemoryBarrier function that makes this class arm
-// specific. Borrowing other MemoryBarrier implementations, this class could
-// be extended to more platforms.
 inline void MemoryBarrier() {
-  // Note: This is a function call, which is also an implicit compiler
+  __asm__ __volatile__ ("dmb ish" ::: "memory");
-  // barrier.
+}
+
+#elif defined(__ARMEL__)
+// From http://src.chromium.org/viewvc/chrome/trunk/src/base/atomicops_internals_arm_gcc.h
+inline void MemoryBarrier() {
+  // Note: This is a function call, which is also an implicit compiler barrier.
   typedef void (*KernelMemoryBarrierFunc)();
   ((KernelMemoryBarrierFunc)0xffff0fa0)();
 }