[Variations] Bring variations_http_header_provider to variations component

components/variations.gypi

Index: components/variations.gypi
diff --git a/components/variations.gypi b/components/variations.gypi
index 2ae6ffca8a6521eea21473505394672bb6f1dbaf..1751336f9ca7a138e6e754225c6041844f6bdcfe 100644
--- a/components/variations.gypi
+++ b/components/variations.gypi
@@ -14,6 +14,7 @@
       'dependencies': [
         '../base/base.gyp:base',
         '../third_party/mt19937ar/mt19937ar.gyp:mt19937ar',
+        'components.gyp:google_core_browser',

[Alexei Svitkine (slow), 2014/07/14 14:13:07]

Sigh, the original intention of this component was to be a very minimal that
depends only on base and the mt19937ar. Now this is pulling in net/ and a lot of
other dependencies. :( 

[Mathieu, 2014/07/14 15:25:13]

Sorry, didn't know this was objectionable :\

[blundell, 2014/07/15 06:44:20]

Alexei, do we want to indirect the call to google_util to go through the client
instead? That way we could avoid pulling in the dependency on the google
component.

[Alexei Svitkine (slow), 2014/07/15 13:56:09]

Possibly. I'm OK living with this for now until the dependency becomes a
problem. (Originally, this component was created so for ChromeOS system
experiments, but that effort hadn't happened. We've also discussed using this
from chrome_elf which also would like minimal dependencies - but again that
didn't materialize.) Let's leave it as-is for now and re-visit if the dependency
becomes a problem.

       ],
       'sources': [
         'variations/active_field_trials.cc',
@@ -32,6 +33,7 @@
         'variations/pref_names.h',
         'variations/processed_study.cc',
         'variations/processed_study.h',
+        'variations/proto/chrome_experiments.proto',
         'variations/proto/permuted_entropy_cache.proto',
         'variations/proto/study.proto',
         'variations/proto/variations_seed.proto',
@@ -39,6 +41,8 @@
         'variations/study_filtering.h',
         'variations/variations_associated_data.cc',
         'variations/variations_associated_data.h',
+        'variations/variations_http_header_provider.cc',
+        'variations/variations_http_header_provider.h',
         'variations/variations_seed_processor.cc',
         'variations/variations_seed_processor.h',
         'variations/variations_seed_simulator.cc',