Expose window size through a headless_shell switch.

BUG=546953

Review-Url: https://codereview.chromium.org/2223563002
Cr-Commit-Position: refs/heads/master@{#410140}

headless/app/headless_shell.cc

@@ -42,7 +42,18 @@ namespace {
 const char kDevToolsHttpServerAddress[] = "127.0.0.1";
 // Default file name for screenshot. Can be overriden by "--screenshot" switch.
 const char kDefaultScreenshotFileName[] = "screenshot.png";
+
+bool ParseWindowSize(std::string window_size, gfx::Size* parsed_window_size) {
+  int width, height = 0;
+  if (sscanf(window_size.c_str(), "%dx%d", &width, &height) >= 2 &&
+      width >= 0 && height >= 0) {
+    parsed_window_size->set_width(width);
+    parsed_window_size->set_height(height);
+    return true;
+  }
+  return false;
 }
+}  // namespace
 
 // A sample application which demonstrates the use of the headless API.
 class HeadlessShell : public HeadlessWebContents::Observer, page::Observer {
@@ -352,6 +363,17 @@ int main(int argc, const char** argv) {
     builder.SetIncognitoMode(false);
   }
 
+  if (command_line.HasSwitch(headless::switches::kWindowSize)) {
+    std::string window_size =
+        command_line.GetSwitchValueASCII(headless::switches::kWindowSize);
+    gfx::Size parsed_window_size;
+    if (!ParseWindowSize(window_size, &parsed_window_size)) {
+      LOG(ERROR) << "Malformed window size";
+      return EXIT_FAILURE;
+    }
+    builder.SetWindowSize(parsed_window_size);
+  }
+
   return HeadlessBrowserMain(
       builder.Build(),
       base::Bind(&HeadlessShell::OnStart, base::Unretained(&shell)));

headless/app/headless_shell_switches.cc

@@ -34,5 +34,8 @@ const char kUseGL[] = "use-gl";
 // Directory where the browser stores the user profile.
 const char kUserDataDir[] = "user-data-dir";
 
+// Sets the initial window size. Provided as string in the format "800x600".
+const char kWindowSize[] = "window-size";
+
 }  // namespace switches
 }  // namespace headless

headless/app/headless_shell_switches.h

@@ -14,6 +14,7 @@ extern const char kRepl[];
 extern const char kScreenshot[];
 extern const char kUseGL[];
 extern const char kUserDataDir[];
+extern const char kWindowSize[];
 }  // namespace switches
 }  // namespace headless