[Blimp] Adds blimp engine browser test framework and LoadUrl test.

blimp/engine/app/blimp_engine_config.cc

Index: blimp/engine/app/blimp_engine_config.cc
diff --git a/blimp/engine/app/blimp_engine_config.cc b/blimp/engine/app/blimp_engine_config.cc
index ccbdc4e52ffbd9a6d007b50382dc0945f2a10f53..8eda1f3ffa694b4e13950f8e464dd84ec7fbd0df 100644
--- a/blimp/engine/app/blimp_engine_config.cc
+++ b/blimp/engine/app/blimp_engine_config.cc
@@ -7,30 +7,52 @@
 #include <memory>
 #include <string>
 
+#include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
 #include "blimp/engine/app/switches.h"
+#include "cc/base/switches.h"
+#include "content/public/common/content_switches.h"
+#include "ui/native_theme/native_theme_switches.h"
 
 namespace blimp {
 namespace engine {
 
 namespace {
-// Gets the client token from the file provided by the command line. If a read
+// Gets the client token from the command line. Either from the token provided,
+// or from the file provided by the command line. If a file read
 // does not succeed, or the switch is malformed, an empty string is returned.
 std::string GetClientToken(const base::CommandLine& cmd_line) {
-  std::string file_contents;
-  const base::FilePath path = cmd_line.GetSwitchValuePath(kClientTokenPath);
-  if (!base::ReadFileToString(path, &file_contents)) {
-    LOG(ERROR) << "Could not read client token file at "
-               << (path.empty() ? "(not provided)" : path.AsUTF8Unsafe());
+  std::string token;
+  if (cmd_line.HasSwitch(kClientToken)) {

[Kevin M, 2016/05/02 21:32:39]

As this is just a test hook, I don't think it's appropriate to add it as a flag.
We chose not to spin up processes running with sensitive data in argv, and it
seems like we shouldn't add logic to enable that. 

Can we plumb it into the client session object, instead?

[haibinlu, 2016/05/03 19:32:43]

reverted. per offline discussion, added a data file for client token.

+    token = cmd_line.GetSwitchValueASCII(kClientToken);
+  } else {
+    DCHECK(cmd_line.HasSwitch(kClientTokenPath));
+    const base::FilePath path = cmd_line.GetSwitchValuePath(kClientTokenPath);
+    if (!base::ReadFileToString(path, &token)) {
+      LOG(ERROR) << "Could not read client token file at "
+                 << (path.empty() ? "(not provided)" : path.AsUTF8Unsafe());
+    }
   }
-  return base::CollapseWhitespaceASCII(file_contents, true);
+  return base::CollapseWhitespaceASCII(token, true);
 }
 }  // namespace
 
+void SetUpCommandLine(base::CommandLine* command_line) {
+  command_line->AppendSwitch(::switches::kEnableOverlayScrollbar);
+  command_line->AppendSwitch(cc::switches::kDisableCachedPictureRaster);
+  command_line->AppendSwitch(::switches::kDisableGpu);
+  command_line->AppendSwitch(
+      "disable-remote-fonts");  // switches::kDisableRemoteFonts is not visible.
+  command_line->AppendSwitch(::switches::kUseRemoteCompositing);
+  command_line->AppendSwitchASCII(
+      ::switches::kUseGL,
+      "osmesa");  // Avoid invoking gpu::CollectDriverVersionNVidia.
+}
+
 BlimpEngineConfig::~BlimpEngineConfig() {}
 
 // static