[chromedriver] Add Network Conditions Override Manager and tests

chrome/test/chromedriver/chrome/web_view.h

Index: chrome/test/chromedriver/chrome/web_view.h
diff --git a/chrome/test/chromedriver/chrome/web_view.h b/chrome/test/chromedriver/chrome/web_view.h
index 718900ee5a8f1ad4ef685766485cf4ae2547658d..47c0cca78a14f54889e22451b371eeedfd55ec44 100644
--- a/chrome/test/chromedriver/chrome/web_view.h
+++ b/chrome/test/chromedriver/chrome/web_view.h
@@ -24,6 +24,7 @@ struct Geoposition;
 class JavaScriptDialogManager;
 struct KeyEvent;
 struct MouseEvent;
+struct NetworkConditions;
 struct TouchEvent;
 class Status;
 
@@ -144,6 +145,10 @@ class WebView {
   // Overrides normal geolocation with a given geoposition.
   virtual Status OverrideGeolocation(const Geoposition& geoposition) = 0;
 
+  // Overrides normal network conditions with given conditions.
+  virtual Status OverrideNetworkConditions(
+      const NetworkConditions& network_conditions) = 0;
+
   // Captures the visible portions of the web view as a base64-encoded PNG.
   virtual Status CaptureScreenshot(std::string* screenshot) = 0;