Adding logging messages for IE driver for bitness mismatches

This commit adds logging messages at the warning level whenever a mismatch
in bitness is detected between the browser and driver. This is a
particularly bad problem in cases where users have 64-bit Windows, and
(incorrectly) assume they automatically want to use the 64-bit
IEDriverServer.exe when running against IE 10 or 11. Since the process
that actually renders content in IE 10 and 11 is almost always 32-bit,
even on 64-bit Windows, it is almost always the proper decision to use
the 32-bit IE driver. It is now very clear from log messages when this
state of affairs exists.

cpp/iedriver/CommandHandlers/ScreenshotCommandHandler.h

@@ -182,6 +182,12 @@ class ScreenshotCommandHandler : public IECommandHandler {
     hook_settings.communication_type = OneWay;
 
     HookProcessor hook;
+    if (!hook.CanSetWindowsHook(ie_window_handle)) {
+      LOG(WARN) << "Screenshot will be truncated! There is a mismatch "
+                << "in the bitness between the driver and browser. In "
+                << "particular, you are likely using a 32-bit "
+                << "IEDriverServer.exe and a 64-bit version of IE.";
+    }
     hook.Initialize(hook_settings);
 
     hook.PushData(sizeof(max_image_dimensions), &max_image_dimensions);

cpp/iedriver/InputManager.cpp

@@ -523,6 +523,14 @@ int InputManager::SendKeystrokes(BrowserHandle browser_wrapper, Json::Value keys
   }
   if (this->enable_native_events()) {
     HWND window_handle = browser_wrapper->GetContentWindowHandle();
+    HookProcessor hook;
+    if (!hook.CanSetWindowsHook(window_handle)) {
+      LOG(WARN) << "SENDING KEYSTROKES WILL BE SLOW! There is a mismatch "
+                << "in the bitness between the driver and browser. In "
+                << "particular, be sure you are not attempting to use a "
+                << "64-bit IEDriverServer.exe against IE 10 or 11, even on "
+                << "64-bit Windows.";
+    }
     if (this->require_window_focus_) {
       LOG(DEBUG) << "Queueing Sendinput structures for sending keys";
       for (unsigned int char_index = 0; char_index < keys.size(); ++char_index) {

cpp/iedriver/ProxyManager.cpp

@@ -231,6 +231,13 @@ void ProxyManager::SetPerProcessProxySettings(HWND browser_window_handle) {
   hook_settings.communication_type = OneWay;
 
   HookProcessor hook;
+  if (!hook.CanSetWindowsHook(browser_window_handle)) {
+    LOG(WARN) << "Proxy will not be set! There is a mismatch in the "
+              << "bitness between the driver and browser. In particular, "
+              << "be sure you are not attempting to use a 64-bit "
+              << "IEDriverServer.exe against IE 10 or 11, even on 64-bit "
+              << "Windows.";
+  }
   hook.Initialize(hook_settings);
   hook.PushData(proxy);
   LRESULT result = ::SendMessage(browser_window_handle,