Add an empty Android implementation of the PhysicalWebDataSource

chrome/test/base/testing_browser_process.cc

Index: chrome/test/base/testing_browser_process.cc
diff --git a/chrome/test/base/testing_browser_process.cc b/chrome/test/base/testing_browser_process.cc
index 843c65a1ccbf8f9395af773b3ce0665a4a4918be..b0e3ca7daa70f683a51ef885ca4da9392a0cffa5 100644
--- a/chrome/test/base/testing_browser_process.cc
+++ b/chrome/test/base/testing_browser_process.cc
@@ -382,6 +382,12 @@ shell_integration::DefaultWebClientState
 TestingBrowserProcess::CachedDefaultWebClientState() {
   return shell_integration::UNKNOWN_DEFAULT;
 }
+
+PhysicalWebDataSource*
+TestingBrowserProcess::GetPhysicalWebDataSource() {
+  return nullptr;
+}
+
 void TestingBrowserProcess::SetSystemRequestContext(
     net::URLRequestContextGetter* context_getter) {
   system_request_context_ = context_getter;