Add compiler flags that prevent text relocations.

Text relocations are a minor security risk. Add compiler flags
that prevent them from reappearing in Android binary.
All existing occurences have been removed after
http://crrev.com/17714003.

TEST=Compile.
BUG=b/8061013

Review URL: https://chromiumcodereview.appspot.com/17820002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@209885 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -2761,10 +2761,14 @@
             ],
             'conditions' : [
               ['OS=="android"', {
-                # Only link with needed input sections. This is to avoid getting
-                # undefined reference to __cxa_bad_typeid in the CDU library.
                 'ldflags': [
+                  '-Wl,--fatal-warnings',
+                  # Only link with needed input sections. This is to avoid
+                  # getting undefined reference to __cxa_bad_typeid in the CDU
+                  # library.
                   '-Wl,--gc-sections',
+                  # Warn in case of text relocations.
+                  '-Wl,--warn-shared-textrel',
                 ],
               }],
               ['OS=="android" and android_full_debug==0', {
@@ -2834,6 +2838,11 @@
                 'cflags': [
                   '-fomit-frame-pointer',
                 ],
+                'ldflags': [
+                  '-Wl,--fatal-warnings',
+                  # Warn in case of text relocations.
+                  '-Wl,--warn-shared-textrel',
+                ],
               }],
               ['clang==1', {
                 'cflags!': [