Revert of Remove a bunch of NPAPI quirks and related support code (patchset #1 id:80001 of https://codereview.chromium.org/1813143002/ )

Reason for revert:
Speculative revert: could have broken Win8 GN build. See crbug.com/597032

Original issue's description:
> Remove a bunch of NPAPI quirks and related support code
>
> BUG=493212
> CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_site_isolation
>
> Committed: https://crrev.com/f8396023a9e38d3ec249cdf1f730e4b79cebbc7e
> Cr-Commit-Position: refs/heads/master@{#382642}

TBR=dcheng@chromium.org,jam@chromium.org,piman@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=493212

Review URL: https://codereview.chromium.org/1825253002

Cr-Commit-Position: refs/heads/master@{#382684}

1 files changed, 52 insertions, 0 deletions

diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index a88549a..e5052e8 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -638,6 +638,9 @@ RenderViewImpl::RenderViewImpl(CompositorDependencies* compositor_deps,
 #if defined(OS_ANDROID)
       expected_content_intent_id_(0),
 #endif
+#if defined(OS_WIN)
+      focused_plugin_id_(-1),
+#endif
 #if defined(ENABLE_PLUGINS)
       focused_pepper_plugin_(NULL),
       pepper_last_mouse_event_target_(NULL),
@@ -1207,6 +1210,15 @@ void RenderViewImpl::UnregisterPluginDelegate(
   plugin_delegates_.erase(delegate);
 }
 
+#if defined(OS_WIN)
+void RenderViewImpl::PluginFocusChanged(bool focused, int plugin_id) {
+  if (focused)
+    focused_plugin_id_ = plugin_id;
+  else
+    focused_plugin_id_ = -1;
+}
+#endif
+
 #if defined(OS_MACOSX)
 void RenderViewImpl::PluginFocusChanged(bool focused, int plugin_id) {
   Send(new ViewHostMsg_PluginFocusChanged(GetRoutingID(), focused, plugin_id));
@@ -2914,6 +2926,32 @@ void RenderViewImpl::OnImeSetComposition(
         text, underlines, selection_start, selection_end);
     return;
   }
+
+#if defined(OS_WIN)
+  // When a plugin has focus, we create platform-specific IME data used by
+  // our IME emulator and send it directly to the focused plugin, i.e. we
+  // bypass WebKit. (WebPluginDelegate dispatches this IME data only when its
+  // instance ID is the same one as the specified ID.)
+  if (focused_plugin_id_ >= 0) {
+    std::vector<int> clauses;
+    std::vector<int> target;
+    for (size_t i = 0; i < underlines.size(); ++i) {
+      clauses.push_back(underlines[i].startOffset);
+      clauses.push_back(underlines[i].endOffset);
+      if (underlines[i].thick) {
+        target.clear();
+        target.push_back(underlines[i].startOffset);
+        target.push_back(underlines[i].endOffset);
+      }
+    }
+    std::set<WebPluginDelegateProxy*>::iterator it;
+    for (it = plugin_delegates_.begin(); it != plugin_delegates_.end(); ++it) {
+      (*it)->ImeCompositionUpdated(text, clauses, target, selection_end,
+                                   focused_plugin_id_);
+    }
+    return;
+  }
+#endif  // OS_WIN
 #endif  // ENABLE_PLUGINS
   if (replacement_range.IsValid() && webview()) {
     // Select the text in |replacement_range|, it will then be replaced by
@@ -2942,6 +2980,20 @@ void RenderViewImpl::OnImeConfirmComposition(
         text, replacement_range, keep_selection);
     return;
   }
+#if defined(OS_WIN)
+  // Same as OnImeSetComposition(), we send the text from IMEs directly to
+  // plugins. When we send IME text directly to plugins, we should not send
+  // it to WebKit to prevent WebKit from controlling IMEs.
+  // TODO(thakis): Honor |replacement_range| for plugins?
+  if (focused_plugin_id_ >= 0) {
+    std::set<WebPluginDelegateProxy*>::iterator it;
+    for (it = plugin_delegates_.begin();
+          it != plugin_delegates_.end(); ++it) {
+      (*it)->ImeCompositionCompleted(text, focused_plugin_id_);
+    }
+    return;
+  }
+#endif  // OS_WIN
 #endif  // ENABLE_PLUGINS
   if (replacement_range.IsValid() && webview()) {
     // Select the text in |replacement_range|, it will then be replaced by