PDF Viewer - Add keyboard shortcuts for rotation

Currently there are no keyboard shortcuts to rotate pdf
documents. This patch adds the following keyboard shortcuts
to rotate pdf documents :

Rotate counterclockwise : Control + [
Rotate clockwise        : Control + ]

BUG=111232

Review URL: https://codereview.chromium.org/581913003

Cr-Commit-Position: refs/heads/master@{#295757}

chrome/browser/resources/pdf/pdf.js

@@ -234,6 +234,16 @@ PDFViewer.prototype = {
           e.preventDefault();
         }
         return;
+      case 219:  // left bracket.
+        this.plugin_.postMessage({
+          type: 'rotateCounterclockwise',
+        });
+        return;
+      case 221:  // right bracket.
+        this.plugin_.postMessage({
+          type: 'rotateClockwise',
+        });
+        return;
     }
   },
 

pdf/instance.cc

@@ -594,6 +594,14 @@ bool Instance::HandleInputEvent(const pp::InputEvent& event) {
       case 'A':
         engine_->SelectAll();
         return true;
+      case ui::VKEY_OEM_4:
+        // Left bracket.
+        engine_->RotateCounterclockwise();
+        return true;
+      case ui::VKEY_OEM_6:
+        // Right bracket.
+        engine_->RotateClockwise();
+        return true;
     }
   }
 

pdf/out_of_process_instance.cc

@@ -124,6 +124,9 @@ const char kJSEmailCc[] = "cc";
 const char kJSEmailBcc[] = "bcc";
 const char kJSEmailSubject[] = "subject";
 const char kJSEmailBody[] = "body";
+// Rotation (Page -> Plugin)
+const char kJSRotateClockwiseType[] = "rotateClockwise";
+const char kJSRotateCounterclockwiseType[] = "rotateCounterclockwise";
 
 const int kFindResultCooldownMs = 100;
 
@@ -374,6 +377,10 @@ void OutOfProcessInstance::HandleMessage(const pp::Var& message) {
     }
   } else if (type == kJSPrintType) {
     Print();
+  } else if (type == kJSRotateClockwiseType) {
+    RotateClockwise();
+  } else if (type == kJSRotateCounterclockwiseType) {
+    RotateCounterclockwise();
   } else if (type == kJSResetPrintPreviewModeType &&
              dict.Get(pp::Var(kJSPrintPreviewUrl)).is_string() &&
              dict.Get(pp::Var(kJSPrintPreviewGrayscale)).is_bool() &&