Reland: Update iOS deployment target to 7.0

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 7e2d4b00dd35062ee4943189e41a815b163fc407..722247f2b6dd9f4357a49390b1bebbe25f7845e8 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1618,7 +1618,7 @@
         # not using the "current" SDK.
         'ios_sdk%': '',
         'ios_sdk_path%': '',
-        'ios_deployment_target%': '6.0',
+        'ios_deployment_target%': '7.0',
 
         'conditions': [
           # ios_product_name is set to the name of the .app bundle as it should
@@ -5020,6 +5020,10 @@
                   'CLANG_CXX_LIBRARY': 'libc++',  # -stdlib=libc++
                 }]
               ],
+            }, {
+              # The default for deployment target of 7.0+ is libc++, so force
+              # the old behavior unless libc++ is enabled.
+              'CLANG_CXX_LIBRARY': 'libstdc++',  # -stdlib=libstdc++
             }],
           ],
         },