headless: expose window size through headless_shell switch.

headless/app/headless_shell.cc

Index: headless/app/headless_shell.cc
diff --git a/headless/app/headless_shell.cc b/headless/app/headless_shell.cc
index 1410313ffa8b663ae36e4f6eb1454a2a551726b1..fb6cba31b420c7499d7cd64d81724e01e3016a9e 100644
--- a/headless/app/headless_shell.cc
+++ b/headless/app/headless_shell.cc
@@ -42,7 +42,14 @@ namespace {
 const char kDevToolsHttpServerAddress[] = "127.0.0.1";
 // Default file name for screenshot. Can be overriden by "--screenshot" switch.
 const char kDefaultScreenshotFileName[] = "screenshot.png";
+
+gfx::Size WindowSizeFromString(std::string window_size) {
+  int width, height = 0;
+  if (sscanf(window_size.c_str(), "%dx%d", &width, &height) >= 2)
+    return gfx::Size(width, height);
+  return gfx::Size();
 }
+}  // namespace
 
 // A sample application which demonstrates the use of the headless API.
 class HeadlessShell : public HeadlessWebContents::Observer, page::Observer {
@@ -352,6 +359,17 @@ 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 = WindowSizeFromString(window_size);
+    if (parsed_window_size.IsEmpty()) {

[Sami, 2016/08/05 18:18:25]

0x0 might be useful in some cases -- could we allow it?

[Eric Seckler, 2016/08/05 18:40:02]

Done.

+      LOG(ERROR) << "Malformed window size";
+      return EXIT_FAILURE;
+    }
+    builder.SetWindowSize(parsed_window_size);
+  }
+
   return HeadlessBrowserMain(
       builder.Build(),
       base::Bind(&HeadlessShell::OnStart, base::Unretained(&shell)));