Pass -Oz flag to Clang when targeting Android.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 1423 matching lines @@
       ]
     }
 
     # Favor size over speed, /O1 must be before the common flags. The GYP
     # build also specifies /Os and /GF but these are implied by /O1.
     cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
   } else if (optimize_for_size && !is_nacl) {
     # Favor size over speed.
     # TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
     # guard above.
-    cflags = [ "-Os" ] + common_optimize_on_cflags
+    if (is_clang) {
+      cflags = [ "-Oz" ] + common_optimize_on_cflags
+    } else {
+      cflags = [ "-Os" ] + common_optimize_on_cflags
+    }
   } else {
     cflags = [ "-O2" ] + common_optimize_on_cflags
   }
   ldflags = common_optimize_on_ldflags
 }
 
 # Same config as 'optimize' but without the WPO flag.
 config("optimize_no_wpo") {
   if (is_win) {
     # Favor size over speed, /O1 must be before the common flags. The GYP
     # build also specifies /Os and /GF but these are implied by /O1.
     cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
   } else if (optimize_for_size && !is_nacl) {
     # Favor size over speed.
     # TODO(crbug.com/718650): Fix -Os in PNaCl compiler and remove the is_nacl
     # guard above.
-    cflags = [ "-Os" ] + common_optimize_on_cflags
+    if (is_clang) {
+      cflags = [ "-Oz" ] + common_optimize_on_cflags
+    } else {
+      cflags = [ "-Os" ] + common_optimize_on_cflags
+    }
   } else if (optimize_for_fuzzing) {
     cflags = [ "-O1" ] + common_optimize_on_cflags
   } else {
     cflags = [ "-O2" ] + common_optimize_on_cflags
   }
   ldflags = common_optimize_on_ldflags
 }
 
 # Turn off optimizations.
 config("no_optimize") {
   if (is_win) {
     cflags = [
       "/Od",  # Disable optimization.
       "/Ob0",  # Disable all inlining (on by default).
       "/GF",  # Enable string pooling (off by default).
     ]
   } else if (is_android && !android_full_debug) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.
-    cflags = [ "-Os" ]
+    if (is_clang) {
+      cflags = [ "-Oz" ] + common_optimize_on_cflags
+    } else {
+      cflags = [ "-Os" ] + common_optimize_on_cflags
+    }
   } else {
     cflags = [ "-O0" ]
     ldflags = []
   }
 }
 
 # Turns up the optimization level. On Windows, this implies whole program
 # optimization and link-time code generation which is very expensive and should
 # be used sparingly.
 config("optimize_max") {
@@ skipping 248 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }