Add PGO targets to Chrome.

This allows to do a PGO optimized build of Chrome with the following commands:
python build\gyp_chromium -Dchrome_pgo_phase=1
ninja -C out\Release chrome
run with '--no-sandbox' + pgosweep
python build\gyp_chromium -Dchrome_pgo_phase=2
ninja -C out\Release chrome


----- Approach that didn't worked -----

(see comment #13 to know why this didn't work)

Instead of having the following gyp dependency chain (for a regular build), here '->' means 'depends on': 

'chrome'->|'chrome_main_dll'
----------|'chrome_child_dll'

we know have the following one (when chrome_pgo==1):
'chrome'->|'chrome_main_dll' |->'chrome_pgo_optimize'->|'chrome_main_dll_pgi'
----------|'chrome_child_dll'|-------------------------|'chrome_child_dll_pgi'


The '*_pgi' target correspond to the instrumented dll, the name of the DLLs produced by target will be terminated by '_pgi'.

During the 'chrome_pgo_optimize' step the instrumented DLLs will be renamed (the '_pgi' suffix will be removed) and Chrome will be run against a set of profile test cases, pgosweep.exe will also be invoked to collect the instrumentation data.

Then the main targets ('chrome_main_dll' and 'chrome_child_dll') will be linked with the flag /LTCG:PGOPTIMIZE, this will produce the optimized DLLs.
--------------------------------------------

R=scottmg@chromium.org

BUG=

Review URL: https://codereview.chromium.org/187813008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257133 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 30 insertions, 0 deletions

diff --git a/chrome/chrome_dll.gypi b/chrome/chrome_dll.gypi
index 13756e1..63887c6 100644
--- a/chrome/chrome_dll.gypi
+++ b/chrome/chrome_dll.gypi
@@ -220,6 +220,20 @@
                     'chrome_dll_pdb_workaround',
                    ],
                 }],
+                ['chrome_pgo_phase==1', {
+                  'msvs_settings': {
+                    'VCLinkerTool': {
+                      'LinkTimeCodeGeneration': '2',
+                    },
+                  },
+                }],
+                ['chrome_pgo_phase==2', {
+                  'msvs_settings': {
+                    'VCLinkerTool': {
+                      'LinkTimeCodeGeneration': '3',
+                    },
+                  },
+                }],
               ]
             }],
             ['chrome_multiple_dll==1', {
@@ -368,6 +382,22 @@
               'dependencies': [
                 '<(DEPTH)/chrome_elf/chrome_elf.gyp:chrome_elf',
               ],
+              'conditions': [
+                ['chrome_pgo_phase==1', {
+                  'msvs_settings': {
+                    'VCLinkerTool': {
+                      'LinkTimeCodeGeneration': '2',
+                    },
+                  },
+                }],
+                ['chrome_pgo_phase==2', {
+                  'msvs_settings': {
+                    'VCLinkerTool': {
+                      'LinkTimeCodeGeneration': '3',
+                    },
+                  },
+                }],
+              ]
             }],
           ],
         },  # target chrome_child_dll