[scheduler] Use Finch to control background throttling.

content/public/common/web_preferences.cc

Index: content/public/common/web_preferences.cc
diff --git a/content/public/common/web_preferences.cc b/content/public/common/web_preferences.cc
index 7a4fe1ef46fd0ad5f0c12004c52d09ad1ea03fa1..1876fe3d1b272b0c6d931275d1ffa56a923b041c 100644
--- a/content/public/common/web_preferences.cc
+++ b/content/public/common/web_preferences.cc
@@ -181,6 +181,10 @@ WebPreferences::WebPreferences()
       animation_policy(IMAGE_ANIMATION_POLICY_ALLOWED),
       user_gesture_required_for_presentation(true),
       text_track_margin_percentage(0.0f),
+      expensive_background_throttling_cpu_budget(-1.0f),
+      expensive_background_throttling_initial_budget(1.0f),

[Sami, 2016/11/03 13:21:15]

Should all of these be negative by default so the scheduler gets to choose the
defaults?

[altimin, 2016/11/04 10:41:25]

In scheduler these values are base::Optional<base::TimeDelta>. Given that we
want to be able to disable these settings via Finch the best way IMO is to set a
sensible default here and treat negative values as base::nullopt and do not
override it in the scheduler.

+      expensive_background_throttling_max_budget(1.0f),
+      expensive_background_throttling_max_delay(-1.0f),
 #if defined(OS_ANDROID)
       text_autosizing_enabled(true),
       font_scale_factor(1.0f),
@@ -216,8 +220,7 @@ WebPreferences::WebPreferences()
       default_minimum_page_scale_factor(1.f),
       default_maximum_page_scale_factor(4.f),
 #endif
-      hide_download_ui(false)
-{
+      hide_download_ui(false) {
   standard_font_family_map[kCommonScript] =
       base::ASCIIToUTF16("Times New Roman");
   fixed_font_family_map[kCommonScript] = base::ASCIIToUTF16("Courier New");