From 41c1623824124cdb5642b77548ad2fb52cbcf47d Mon Sep 17 00:00:00 2001
From: deepak1556 <hop2deep@gmail.com>
Date: Wed, 18 Jan 2017 21:55:36 +0530
Subject: [PATCH] handle more messages from webui

---
 atom/browser/ui/webui/pdf_viewer_handler.cc | 56 +++++++++++++++++++--
 atom/browser/ui/webui/pdf_viewer_handler.h  | 11 +++-
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/atom/browser/ui/webui/pdf_viewer_handler.cc b/atom/browser/ui/webui/pdf_viewer_handler.cc
index 611acd8eeb8d..82c80d7a81a4 100644
--- a/atom/browser/ui/webui/pdf_viewer_handler.cc
+++ b/atom/browser/ui/webui/pdf_viewer_handler.cc
@@ -9,6 +9,7 @@
 #include "base/values.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_ui.h"
+#include "content/public/common/page_zoom.h"
 
 namespace atom {
 
@@ -23,8 +24,23 @@ void PdfViewerHandler::RegisterMessages() {
       "initialize",
       base::Bind(&PdfViewerHandler::Initialize, base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
-      "getTabId",
-      base::Bind(&PdfViewerHandler::GetTabId, base::Unretained(this)));
+      "getDefaultZoom",
+      base::Bind(&PdfViewerHandler::GetInitialZoom, base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "getInitialZoom",
+      base::Bind(&PdfViewerHandler::GetInitialZoom, base::Unretained(this)));
+}
+
+void PdfViewerHandler::OnJavascriptAllowed() {
+  auto host_zoom_map =
+      content::HostZoomMap::GetForWebContents(web_ui()->GetWebContents());
+  host_zoom_map_subscription_ =
+      host_zoom_map->AddZoomLevelChangedCallback(base::Bind(
+          &PdfViewerHandler::OnZoomLevelChanged, base::Unretained(this)));
+}
+
+void PdfViewerHandler::OnJavascriptDisallowed() {
+  host_zoom_map_subscription_.reset();
 }
 
 void PdfViewerHandler::Initialize(const base::ListValue* args) {
@@ -39,13 +55,45 @@ void PdfViewerHandler::Initialize(const base::ListValue* args) {
   ResolveJavascriptCallback(*callback_id, *stream_info);
 }
 
-void PdfViewerHandler::GetTabId(const base::ListValue* args) {
+void PdfViewerHandler::GetDefaultZoom(const base::ListValue* args) {
   if (!IsJavascriptAllowed())
     return;
   CHECK_EQ(1U, args->GetSize());
   const base::Value* callback_id;
   CHECK(args->Get(0, &callback_id));
-  ResolveJavascriptCallback(*callback_id, base::FundamentalValue(-1));
+
+  auto host_zoom_map =
+      content::HostZoomMap::GetForWebContents(web_ui()->GetWebContents());
+  double zoom_level = host_zoom_map->GetDefaultZoomLevel();
+  ResolveJavascriptCallback(
+      *callback_id,
+      base::FundamentalValue(content::ZoomLevelToZoomFactor(zoom_level)));
+}
+
+void PdfViewerHandler::GetInitialZoom(const base::ListValue* args) {
+  if (!IsJavascriptAllowed())
+    return;
+  CHECK_EQ(1U, args->GetSize());
+  const base::Value* callback_id;
+  CHECK(args->Get(0, &callback_id));
+
+  double zoom_level =
+      content::HostZoomMap::GetZoomLevel(web_ui()->GetWebContents());
+  ResolveJavascriptCallback(
+      *callback_id,
+      base::FundamentalValue(content::ZoomLevelToZoomFactor(zoom_level)));
+}
+
+void PdfViewerHandler::OnZoomLevelChanged(
+    const content::HostZoomMap::ZoomLevelChange& change) {
+  // TODO(deepak1556): This will work only if zoom level is changed through host
+  // zoom map.
+  if (change.scheme == "chrome" && change.host == "pdf-viewer") {
+    CallJavascriptFunction(
+        "cr.webUIListenerCallback", base::StringValue("onZoomLevelChanged"),
+        base::FundamentalValue(
+            content::ZoomLevelToZoomFactor(change.zoom_level)));
+  }
 }
 
 }  // namespace atom
diff --git a/atom/browser/ui/webui/pdf_viewer_handler.h b/atom/browser/ui/webui/pdf_viewer_handler.h
index c7661fdcda2c..10e376d0918a 100644
--- a/atom/browser/ui/webui/pdf_viewer_handler.h
+++ b/atom/browser/ui/webui/pdf_viewer_handler.h
@@ -7,8 +7,8 @@
 
 #include <string>
 
-#include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/web_ui_message_handler.h"
 
 namespace base {
@@ -25,11 +25,18 @@ class PdfViewerHandler : public content::WebUIMessageHandler {
 
   // WebUIMessageHandler implementation.
   void RegisterMessages() override;
+  void OnJavascriptAllowed() override;
+  void OnJavascriptDisallowed() override;
 
  private:
   void Initialize(const base::ListValue* args);
-  void GetTabId(const base::ListValue* args);
+  void GetDefaultZoom(const base::ListValue* args);
+  void GetInitialZoom(const base::ListValue* args);
+  void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
 
+  // Keeps track of events related to zooming.
+  std::unique_ptr<content::HostZoomMap::Subscription>
+      host_zoom_map_subscription_;
   std::string stream_url_;
   std::string original_url_;