Roll clang 277962:278861

BUG=636558,637866

Review-Url: https://codereview.chromium.org/2241413003
Cr-Commit-Position: refs/heads/master@{#412745}

base/threading/thread_unittest.cc

@@ -137,8 +137,9 @@ TEST_F(ThreadTest, StartWithOptions_StackSize) {
   // Ensure that the thread can work with only 12 kb and still process a
   // message.
   Thread::Options options;
-#if defined(ADDRESS_SANITIZER)
-  // ASan bloats the stack variables and overflows the 12 kb stack.
+#if defined(ADDRESS_SANITIZER) || (defined(OS_IOS) && !defined(NDEBUG))
+  // ASan bloats the stack variables and overflows the 12 kb stack. Debug iOS
+  // builds also grow the stack too much.
   options.stack_size = 24*1024;
 #else
   options.stack_size = 12*1024;

build/config/compiler/BUILD.gn

@@ -1014,13 +1014,10 @@ config("default_warnings") {
 
         # TODO(thakis): https://crbug.com/617318
         "-Wno-nonportable-include-path",
+
+        # TODO(hans): https://crbug.com/637306
+        "-Wno-address-of-packed-member",
       ]
-      if (llvm_force_head_revision) {
-        cflags += [
-          # TODO(hans): https://crbug.com/637306
-          "-Wno-address-of-packed-member",
-        ]
-      }
     }
   }
 }

tools/clang/scripts/update.py

@@ -27,7 +27,7 @@ import zipfile
 # Do NOT CHANGE this if you don't know what you're doing -- see
 # https://chromium.googlesource.com/chromium/src/+/master/docs/updating_clang.md
 # Reverting problematic clang rolls is safe, though.
-CLANG_REVISION = '277962'
+CLANG_REVISION = '278861'
 
 use_head_revision = 'LLVM_FORCE_HEAD_REVISION' in os.environ
 if use_head_revision: