Make it possible to read CLD data from a file

chrome/renderer/translate/translate_helper.h

Index: chrome/renderer/translate/translate_helper.h
diff --git a/chrome/renderer/translate/translate_helper.h b/chrome/renderer/translate/translate_helper.h
index 88dd518cf69ab98019089428ef253b0121894002..85a55e4410d15d8f433bb47141910d238a0b1ccc 100644
--- a/chrome/renderer/translate/translate_helper.h
+++ b/chrome/renderer/translate/translate_helper.h
@@ -7,11 +7,14 @@
 
 #include <string>
 
+#include "base/files/memory_mapped_file.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "components/translate/core/common/translate_errors.h"
 #include "content/public/renderer/render_view_observer.h"
+#include "ipc/ipc_platform_file.h"
+#include "url/gurl.h"
 
 namespace blink {
 class WebDocument;
@@ -29,6 +32,11 @@ class TranslateHelper : public content::RenderViewObserver {
   // Informs us that the page's text has been extracted.
   void PageCaptured(int page_id, const base::string16& contents);
 
+  // Lets the translation system know that we are preparing to navigate to
+  // the specified URL. If there is anything that can or should be done before
+  // this URL loads, this is the time to prepare for it.
+  void PrepareForUrl(const GURL& url);
+
  protected:
   // The following methods are protected so they can be overridden in
   // unit-tests.
@@ -148,6 +156,60 @@ class TranslateHelper : public content::RenderViewObserver {
   // Method factory used to make calls to TranslatePageImpl.
   base::WeakPtrFactory<TranslateHelper> weak_method_factory_;
 
+#if defined(CLD2_DYNAMIC_MODE)
+  // Do not ask for CLD data any more.
+  void CancelCLD2DataFilePolling();
+
+  // Whether or not polling for CLD2 data has started.
+  bool cld2_data_file_polling_started_;
+
+  // Whether or not CancelCLD2DataFilePolling has been called.
+  bool cld2_data_file_polling_canceled_;
+
+  // Whether or not a PageCaptured event arrived prior to CLD data becoming
+  // available. If true, deferred_page_id_ contains the most recent page ID
+  // and deferred_contents_ contains the most recent contents.
+  bool deferred_page_capture_;
+
+  // The ID of the page most recently reported to PageCaptured if
+  // deferred_page_capture_ is true.
+  int deferred_page_id_;
+
+  // The contents of the page most recently reported to PageCaptured if
+  // deferred_page_capture_ is true.
+  base::string16 deferred_contents_;
+
+  // The mmap. The mmap dstructor will unmap the memory segment and close the

[palmer, 2014/03/24 19:01:47]

Nit: typo "destructor".

[Andrew Hayden (chromium.org), 2014/03/26 15:34:11]

Done.

+  // file handle; it must be held throughought the lifetime of the process.

[bulach, 2014/03/25 09:29:26]

I think valgrind and friends will complain about this object being leaked.
LazyInstance::Leaky is the pattern used for this kind of objects, it annotates
correctly so that the leak detection tools won't flag them.

[Andrew Hayden (chromium.org), 2014/03/26 15:34:11]

So.... LazyInstance:Leaky of a pointer? I'll talk to you offline, the rabbit
hole is too deep for a comment thread.

+  static base::MemoryMappedFile* s_cld2_data_file_mmap_;

[bulach, 2014/03/25 09:29:26]

nit: also, please move the fields (164-184) after the methods.

[Andrew Hayden (chromium.org), 2014/03/26 15:34:11]

Done.

+
+  // Invoked when PageCaptured is called prior to obtaining CLD data. This
+  // method stores the page ID into deferred_page_id_ and COPIES the contents
+  // of the page, then sets deferred_page_capture_ to true. When CLD data is
+  // eventually received (in OnCLDDataAvailable), any deferred request will be
+  // "resurrected" and allowed to proceed automatically, assuming that the
+  // page ID has not changed.
+  void DeferPageCaptured(const int page_id, const base::string16& contents);
+
+  // Immediately send an IPC request to the browser process to get the CLD
+  // data file. In most cases, the file will already exist and we will only
+  // poll once; but since the file might need to be downloaded first, poll
+  // indefinitely until a ChromeViewMsg_CLDDataAvailable message is received
+  // from the browser process.
+  // Polling will automatically halt as soon as the renderer obtains a
+  // reference to the data file.
+  void SendCLD2DataFileRequest(int delay_millis, int next_delay_millis);
+
+  // Invoked when a ChromeViewMsg_CLDDataAvailable message is received from
+  // the browser process, providing a file handle for the CLD data file. If a
+  // PageCaptured request was previously deferred with DeferPageCaptured and
+  // the page ID has not yet changed, the PageCaptured is reinvoked to
+  // "resurrect" the language detection pathway.
+  void OnCLDDataAvailable(IPC::PlatformFileForTransit ipc_file_handle);
+
+  // After receiving data in OnCLDDataAvailable, loads the data into CLD2.
+  void LoadCLDDData(IPC::PlatformFileForTransit ipc_file_handle);
+#endif

[palmer, 2014/03/24 19:01:47]

Nit: Should be a blank line after this.

[Andrew Hayden (chromium.org), 2014/03/26 15:34:11]

Done.

   DISALLOW_COPY_AND_ASSIGN(TranslateHelper);
 };