mandoline: Fix character entry in html_viewer on Linux.

This reverts my previous change (https://codereview.chromium.org/1232703006),
which fixed the double character insertion in the mandoline omnibox, but
broke all text entry in the html_viewer. The correct change was to make
sure we're using an InputMethodMandoline.

In https://codereview.chromium.org/1155013005/, InputMethodMandoline
appears to have been removed by accident while removing
InputMethodEventFilter. However, at least on Linux, we need to *not* use
InputMethodAuraLinux, which operates on a stream of X11 events, instead
of a stream of events that is designed to look like Windows events on
all platforms.

We don't see these problems on Windows because InputMethodWin is already
expecting a stream of events that looks like what Windows natively sends.

BUG=none

Review URL: https://codereview.chromium.org/1234623004

Cr-Commit-Position: refs/heads/master@{#339672}

components/view_manager/display_manager.cc

@@ -278,6 +278,39 @@ void DefaultDisplayManager::DispatchEvent(ui::Event* event) {
     default:
       break;
   }
+
+#if defined(USE_X11)
+  // We want to emulate the WM_CHAR generation behaviour of Windows.
+  //
+  // On Linux, we've previously inserted characters by having
+  // InputMethodAuraLinux take all key down events and send a character event
+  // to the TextInputClient. This causes a mismatch in code that has to be
+  // shared between Windows and Linux, including blink code. Now that we're
+  // trying to have one way of doing things, we need to standardize on and
+  // emulate Windows character events.
+  //
+  // This is equivalent to what we're doing in the current Linux port, but
+  // done once instead of done multiple times in different places.
+  if (event->type() == ui::ET_KEY_PRESSED) {
+    ui::KeyEvent* key_press_event = static_cast<ui::KeyEvent*>(event);
+    ui::KeyEvent char_event(key_press_event->GetCharacter(),
+                            key_press_event->key_code(),
+                            key_press_event->flags());
+
+    DCHECK_EQ(key_press_event->GetCharacter(), char_event.GetCharacter());
+    DCHECK_EQ(key_press_event->key_code(), char_event.key_code());
+    DCHECK_EQ(key_press_event->flags(), char_event.flags());
+
+    char_event.SetExtendedKeyEventData(
+        make_scoped_ptr(new mojo::MojoExtendedKeyEventData(
+            key_press_event->GetLocatedWindowsKeyboardCode(),
+            key_press_event->GetText(),
+            key_press_event->GetUnmodifiedText())));
+    char_event.set_platform_keycode(key_press_event->platform_keycode());
+
+    delegate_->OnEvent(mojo::Event::From(char_event));
+  }
+#endif
 }
 
 void DefaultDisplayManager::OnCloseRequest() {

mandoline/ui/aura/window_tree_host_mojo.cc

@@ -5,6 +5,7 @@
 #include "mandoline/ui/aura/window_tree_host_mojo.h"
 
 #include "components/view_manager/public/cpp/view_manager.h"
+#include "mandoline/ui/aura/input_method_mandoline.h"
 #include "mandoline/ui/aura/surface_context_factory.h"
 #include "mojo/application/public/interfaces/shell.mojom.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
@@ -33,6 +34,9 @@ WindowTreeHostMojo::WindowTreeHostMojo(mojo::Shell* shell, mojo::View* view)
   CreateCompositor(GetAcceleratedWidget());
   aura::Env::GetInstance()->set_context_factory(default_context_factory);
   DCHECK_EQ(context_factory_.get(), compositor()->context_factory());
+
+  input_method_.reset(new InputMethodMandoline(this));
+  SetSharedInputMethod(input_method_.get());
 }
 
 WindowTreeHostMojo::~WindowTreeHostMojo() {

mandoline/ui/aura/window_tree_host_mojo.h

@@ -23,6 +23,7 @@ class Shell;
 
 namespace mandoline {
 
+class InputMethodMandoline;
 class SurfaceContextFactory;
 
 class WindowTreeHostMojo : public aura::WindowTreeHost,
@@ -61,6 +62,8 @@ class WindowTreeHostMojo : public aura::WindowTreeHost,
 
   gfx::Rect bounds_;
 
+  scoped_ptr<InputMethodMandoline> input_method_;
+
   scoped_ptr<SurfaceContextFactory> context_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMojo);