Add Link-Time Optimizations support for Android.

build/android/increase_size_for_speed.gypi

Index: build/android/increase_size_for_speed.gypi
diff --git a/build/android/increase_size_for_speed.gypi b/build/android/increase_size_for_speed.gypi
index f5f2d6263322bd53270e1bc38348619e800113dc..3030234474f2e9705d1c7099713bc4b8638cfc91 100644
--- a/build/android/increase_size_for_speed.gypi
+++ b/build/android/increase_size_for_speed.gypi
@@ -18,6 +18,19 @@
               'cflags!': ['-Os'],
               'cflags': ['-O2'],
             }],
+            # Do not merge -Os and -O2 in LTO

[pasko, 2014/10/10 11:59:21]

s/LTO/LTO./

Also you can briefly explain, like:
All objects that were compiled with LTO will be forced to have the same
optimization flags at link time with a stupid algorithm. Avoid using LTO
simultaneously on -Os and -O2 parts for that reason.

[Fabrice (no longer in Chrome), 2014/10/13 15:45:12]

Done.

+            ['use_lto==1', {

[pasko, 2014/10/10 11:59:21]

maybe this should be called use_lto_os? I understand that there is code
committed to other repos that name this thing 'use_lto'. Maybe put an 'alias' in
common.gypi to have use_lto_os, and use_lto be aliases? Or maybe just an
explanation in the comment there for the start?

[Fabrice (no longer in Chrome), 2014/10/13 15:45:12]

I think it's too late for that at this point. The bot uses use_lto, the other
repos use use_lto. I added a note in common.gypi explaining the difference
between the two.

+              'cflags!': [
+                '-flto',
+                '-ffat-lto-objects',
+              ],
+            }],
+            ['use_lto_o2==1', {
+              'cflags': [
+                '-flto',
+                '-ffat-lto-objects',
+              ],
+            }],
           ],
         }],
       ],