Fix SizeLabelToMinWidth() function such that no unnecessary space

chrome/browser/ui/views/download/download_item_view.cc

Index: chrome/browser/ui/views/download/download_item_view.cc
diff --git a/chrome/browser/ui/views/download/download_item_view.cc b/chrome/browser/ui/views/download/download_item_view.cc
index 99b5344d90e8e6a49eaaed4000c68bd01650753a..5e1f2989933c8082664edf2513f786a67f3afef3 100644
--- a/chrome/browser/ui/views/download/download_item_view.cc
+++ b/chrome/browser/ui/views/download/download_item_view.cc
@@ -183,7 +183,7 @@ DownloadItemView::DownloadItemView(DownloadItem* download_item,
       save_button_(nullptr),
       discard_button_(nullptr),
       dropdown_button_(new DropDownButton(this)),
-      dangerous_download_label_(nullptr),
+      dangerous_download_label_(new views::Label()),
       dangerous_download_label_sized_(false),
       disabled_while_opening_(false),
       creation_time_(base::Time::Now()),
@@ -223,6 +223,9 @@ DownloadItemView::~DownloadItemView() {
   // without keeping it.
   if (sampling_event_)
     sampling_event_->CreateUserDecisionEvent(ExperienceSamplingEvent::kIgnore);
+
+  delete dangerous_download_label_;
+  dangerous_download_label_ = nullptr;

[Peter Kasting, 2016/12/08 05:10:23]

This potentially double-frees.  Views is expecting to own the pointer you pass
to AddChildView().  You could get around this by marking it as "owned by parent"
(and changing the class member to a unique_ptr), but the best way, I think, is
to move _all_ the code for |dangerous_download_label_| to the constructor,
including the AddChildView() call, and then either moving the other calls that
add children there as well, or else modifying them so they insert their children
in a specific place in the child list instead of at the end using
AddChildViewAt().

[Jialiu Lin, 2016/12/08 07:47:40]

Ack.

 }
 
 // Progress animation handlers.
@@ -343,7 +346,8 @@ void DownloadItemView::OnDownloadUpdated(DownloadItem* download_item) {
 }
 
 void DownloadItemView::OnDownloadDestroyed(DownloadItem* download) {
-  shelf_->RemoveDownloadView(this);  // This will delete us!
+  if (shelf_)
+    shelf_->RemoveDownloadView(this);  // This will delete us!
 }
 
 void DownloadItemView::OnDownloadOpened(DownloadItem* download) {
@@ -795,12 +799,16 @@ void DownloadItemView::SubmitDownloadWhenFeedbackServiceEnabled(
 }
 
 void DownloadItemView::LoadIcon() {
-  IconManager* im = g_browser_process->icon_manager();
-  last_download_item_path_ = download()->GetTargetFilePath();
-  im->LoadIcon(last_download_item_path_, IconLoader::SMALL,
-               base::Bind(&DownloadItemView::OnExtractIconComplete,
-                          base::Unretained(this)),
-               &cancelable_task_tracker_);
+  // If there is no download shelf assigned, this is called in a test, then no
+  // need to load the icon.

[Peter Kasting, 2016/12/08 05:10:23]

Does it actually hurt to load this icon in a test?

If not, I would just do that.

If so, maybe we should not key off |shelf_|, which seems like an indirect way to
be checking that this is in a test?  Should there be some kind of variable that
directly says if we're in a test?

[Jialiu Lin, 2016/12/08 07:47:40]

Unfortunately LoadIcon function involves shelf_. So in the new constructor, this
function will not be called. 

+  if (shelf_) {
+    IconManager* im = g_browser_process->icon_manager();
+    last_download_item_path_ = download()->GetTargetFilePath();
+    im->LoadIcon(last_download_item_path_, IconLoader::SMALL,
+                 base::Bind(&DownloadItemView::OnExtractIconComplete,
+                            base::Unretained(this)),
+                 &cancelable_task_tracker_);
+  }
 }
 
 void DownloadItemView::LoadIconIfItemPathChanged() {
@@ -970,7 +978,7 @@ void DownloadItemView::ShowWarningDialog() {
 
   base::string16 dangerous_label =
       model_.GetWarningText(font_list_, kTextWidth);
-  dangerous_download_label_ = new views::Label(dangerous_label);
+  dangerous_download_label_->SetText(dangerous_label);
   dangerous_download_label_->SetMultiLine(true);
   dangerous_download_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
   dangerous_download_label_->SetAutoColorReadabilityEnabled(false);
@@ -1016,6 +1024,18 @@ void DownloadItemView::SizeLabelToMinWidth() {
   if (dangerous_download_label_sized_)
     return;
 
+  dangerous_download_label_->SetSize(GetLabelSize());
+  dangerous_download_label_sized_ = true;
+}
+
+gfx::Size DownloadItemView::GetLabelSize() {
+  gfx::Size size = dangerous_download_label_->GetPreferredSize();
+
+  // If the label is already narrower than kDangerousTextWidth, we don't need to
+  // linebreak it, as it will fit on a single line.
+  if (size.width() <= kDangerousTextWidth)
+    return size;
+
   base::string16 label_text = dangerous_download_label_->text();
   base::TrimWhitespace(label_text, base::TRIM_ALL, &label_text);
   DCHECK_EQ(base::string16::npos, label_text.find('\n'));
@@ -1035,16 +1055,11 @@ void DownloadItemView::SizeLabelToMinWidth() {
   bool status = iter.Init();
   DCHECK(status);
 
-  base::string16 prev_text = original_text;
-  gfx::Size size = dangerous_download_label_->GetPreferredSize();
-  int min_width = size.width();
-
   // Go through the string and try each line break (starting with no line break)
-  // searching for the optimal line break position.  Stop if we find one that
-  // yields one that is less than kDangerousTextWidth wide.  This is to prevent
-  // a short string (e.g.: "This file is malicious") from being broken up
-  // unnecessarily.
-  while (iter.Advance() && min_width > kDangerousTextWidth) {
+  // searching for the optimal line break position. Stop if we find one that
+  // yields minimum label width.
+  base::string16 prev_text = original_text;
+  for (gfx::Size min_width_size = size; iter.Advance(); min_width_size = size) {
     size_t pos = iter.pos();
     if (pos >= original_text.length())
       break;
@@ -1061,17 +1076,13 @@ void DownloadItemView::SizeLabelToMinWidth() {
     size = dangerous_download_label_->GetPreferredSize();
 
     // If the width is growing again, it means we passed the optimal width spot.
-    if (size.width() > min_width) {
+    if (size.width() > min_width_size.width()) {
       dangerous_download_label_->SetText(prev_text);
-      break;
-    } else {
-      min_width = size.width();
+      return min_width_size;
     }
     prev_text = current_text;
   }
-
-  dangerous_download_label_->SetSize(size);
-  dangerous_download_label_sized_ = true;
+  return size;
 }
 
 void DownloadItemView::Reenable() {