Replace OnPageTranslate Obsever by a responder of delegate.

chrome/browser/ui/android/infobars/translate_compact_infobar.h

Index: chrome/browser/ui/android/infobars/translate_compact_infobar.h
diff --git a/chrome/browser/ui/android/infobars/translate_compact_infobar.h b/chrome/browser/ui/android/infobars/translate_compact_infobar.h
index aeabb616fe27b7a9b09335e18414955f6212d4bf..be5fce1c6ed90db49f596e95aa3a4255fa081655 100644
--- a/chrome/browser/ui/android/infobars/translate_compact_infobar.h
+++ b/chrome/browser/ui/android/infobars/translate_compact_infobar.h
@@ -9,7 +9,9 @@
 #include "base/macros.h"
 #include "chrome/browser/translate/chrome_translate_client.h"
 #include "chrome/browser/ui/android/infobars/infobar_android.h"
-#include "components/translate/content/browser/content_translate_driver.h"
+#include "components/translate/core/browser/translate_infobar_delegate.h"
+#include "components/translate/core/browser/translate_step.h"
+#include "components/translate/core/common/translate_errors.h"
 
 namespace translate {
 class TranslateInfoBarDelegate;
@@ -17,7 +19,7 @@ class TranslateInfoBarDelegate;
 
 class TranslateCompactInfoBar
     : public InfoBarAndroid,
-      public translate::ContentTranslateDriver::Observer {
+      public translate::TranslateInfoBarDelegate::Responder {
  public:
   explicit TranslateCompactInfoBar(
       std::unique_ptr<translate::TranslateInfoBarDelegate> delegate);
@@ -44,10 +46,10 @@ class TranslateCompactInfoBar
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj);
 
-  // ContentTranslateDriver::Observer implementation.
-  void OnPageTranslated(const std::string& original_lang,

[groby-ooo-7-16, 2017/05/20 21:30:39]

Who is notifying the ContentTranslateDriver now?

[Leo, 2017/05/21 04:15:20]

This method is used when ContentTranslateDriver finished translation and notify
the observer to update its state.

With or without a observer, translate manager will be called when page
translation finished. 
https://cs.chromium.org/chromium/src/components/translate/content/browser/con...

So the following things will always happen with or without observer.

ContentTranslateDriver:OnPageTranslated  >> 
TranslateManager::PageTranslated >>
TranslateClient::ShowTranslateUI >>
TranslateInfoBarDelegate::Create

So I remove this observer stuff in compact infobar but respond the
onPageTranslated event inside TranslateInfoBarDelegate

-                        const std::string& translated_lang,
-                        translate::TranslateErrors::Type error_type) override;
+  // TranslateInfoBarDelegate::Responder implementation.
+  void ActionOnStep(translate::TranslateStep step,
+                    translate::TranslateErrors::Type error_type) override;
+  bool Declined() override;
 
  private:
   // InfoBarAndroid:
@@ -58,7 +60,19 @@ class TranslateCompactInfoBar
       const base::android::JavaRef<jobject>& java_info_bar) override;
 
   translate::TranslateInfoBarDelegate* GetDelegate();
-  translate::ContentTranslateDriver* translate_driver_;
+
+  // Bits for trace user actions.
+  unsigned int action_flags_;

[groby-ooo-7-16, 2017/05/20 21:30:39]

This should be of type ActionFlag if you use the enum.

As a _personal_ preference, I'd prefer a bitfield. But ultimately, either is
fine.
 struct {
    bool did_translate_ : 1;
    bool did_revert_ : 1;
    ...
  } flags;

[napper, 2017/05/21 23:24:16]

I think the int type is correct here, since the enum specifies bit flags, not
values. The following would not be correct for an enum but is correct for an int
type:

action_flags_ = FLAG_TRANSLATE | FLAG_NEVER_LANGUAGE;

But I agree, a bitfield might be cleaner.

[Leo, 2017/05/22 09:08:10]

After a little discuss offline with Jon. Seems the initialization of the struct
is not as simple as int and it may introduce other considerations. How about let
me keep this way and refactor it in another CL.

[groby-ooo-7-16, 2017/05/22 14:34:11]

You are of course right about the int - sorry about the confusion.

[groby-ooo-7-16, 2017/05/22 14:34:11]

No need to refactor if it introduces many other issues. (As I said, it's a
personal preference of mine - but just because I like something a bit better
aesthethically doesn't mean you should have a lot of extra work :)

+
+  // User action flags to record what the user has done in each session.
+  enum ActionFlag {
+    FLAG_NONE = 0,
+    FLAG_TRANSLATE = 1 << 0,
+    FLAG_REVERT = 1 << 1,
+    FLAG_ALWAYS_TRANSLATE = 1 << 2,
+    FLAG_NEVER_LANGUAGE = 1 << 3,
+    FLAG_NEVER_SITE = 1 << 4,
+  };
 
   // If number of consecutive translations is equal to this number, infobar will
   // automatically trigger "Always Translate".