Makes sure the keyboard typing isn't blocked when InputMethod::OnFocus() is not correctly called.

ui/base/ime/input_method_log_collector.cc

Index: ui/base/ime/input_method_log_collector.cc
diff --git a/ui/base/ime/input_method_log_collector.cc b/ui/base/ime/input_method_log_collector.cc
new file mode 100644
index 0000000000000000000000000000000000000000..40e9429d169aa6e1189e71e63ba7cc78124e157f
--- /dev/null
+++ b/ui/base/ime/input_method_log_collector.cc
@@ -0,0 +1,47 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/base/ime/input_method_log_collector.h"
+
+#include <string.h>
+
+#include "base/debug/alias.h"
+#include "base/debug/dump_without_crashing.h"
+
+namespace ui {
+
+InputMethodLogCollector::InputMethodLogCollector() {}
+
+InputMethodLogCollector::~InputMethodLogCollector() {}
+
+void InputMethodLogCollector::AddLog(const std::string& log_string) {
+  logs_.push_back(log_string);
+}
+
+void InputMethodLogCollector::DumpLogs() {
+  if (logs_.empty())

[eroman, 2016/01/13 22:27:08]

Is knowing that the logs_ was empty useful in itself? If so might want to copy
logs_.size() to a stack variable and dump anyway in this case.

[Shu Chen, 2016/01/14 07:44:47]

Done.

+    return;
+
+  char logs_copy[4096];

[eroman, 2016/01/13 22:27:08]

See suggestion for using string literals (const char*).

If you go that approach, should be sufficient to instead copy a const char*
logs_copy[<max-logs>], without needing to copy the string content itself to the
stack

[Shu Chen, 2016/01/14 07:44:47]

Done.

+  size_t copy_from = 0;
+  for (size_t i = 0; i < logs_.size() && copy_from < sizeof(logs_copy); ++i) {

[eroman, 2016/01/13 22:27:08]

I didn't review this yet (in case you change to the other approach).

[Shu Chen, 2016/01/14 07:44:47]

Done.

+    strncpy(logs_copy + copy_from, logs_[i].c_str(),
+            sizeof(logs_copy) - copy_from);
+    copy_from += logs_[i].length();
+    if (copy_from >= sizeof(logs_copy))
+      break;
+    strncpy(logs_copy + copy_from, "; ",
+            sizeof(logs_copy) - copy_from);
+    copy_from += 2;
+  }
+  logs_.clear();
+  base::debug::Alias(&logs_copy);
+  base::debug::DumpWithoutCrashing();

[eroman, 2016/01/13 22:27:08]

How often do you expect this to be hit? Do you have an estimate for how many
crash dumps it will generate for users?

If this is called often, it will be a problem for users (as
DumpWithoutCrashing() is expensive and can stall the application).
I would recommend adding some sort of safety net: either a maximum number of
times that DumpWithoutCrashing() will be called here (i.e. counter), or use
randomness to call this only on some percentage of times reached.

[Shu Chen, 2016/01/14 07:44:47]

Done. I've made it only dump 5 times at maximum.

+}
+
+void InputMethodLogCollector::ClearLogs() {
+  logs_.clear();
+}
+
+}  // namespace ui