Allow empty strings to be written to the clipboard

BUG=109810
TEST=manual testing


Review URL: https://chromiumcodereview.appspot.com/10532168

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@142554 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 81 insertions, 64 deletions

diff --git a/content/browser/web_contents/web_contents_drag_win.cc b/content/browser/web_contents/web_contents_drag_win.cc
index a68faaa..99c9bd6 100644
--- a/content/browser/web_contents/web_contents_drag_win.cc
+++ b/content/browser/web_contents/web_contents_drag_win.cc
@@ -282,12 +282,12 @@ void WebContentsDragWin::DoDragging(const WebDropData& drop_data,
     // a shortcut so we add it first.
     if (!drop_data.file_contents.empty())
       PrepareDragForFileContents(drop_data, &data);
-    if (!drop_data.text_html.empty())
-      data.SetHtml(drop_data.text_html, drop_data.html_base_url);
+    if (!drop_data.html.string().empty())
+      data.SetHtml(drop_data.html.string(), drop_data.html_base_url);
     // We set the text contents before the URL because the URL also sets text
     // content.
-    if (!drop_data.plain_text.empty())
-      data.SetString(drop_data.plain_text);
+    if (!drop_data.text.string().empty())
+      data.SetString(drop_data.text.string());
     if (drop_data.url.is_valid())
       PrepareDragForUrl(drop_data, &data);
     if (!drop_data.custom_data.empty()) {
diff --git a/content/browser/web_contents/web_contents_view_aura.cc b/content/browser/web_contents/web_contents_view_aura.cc
index 101e58b..448c145 100644
--- a/content/browser/web_contents/web_contents_view_aura.cc
+++ b/content/browser/web_contents/web_contents_view_aura.cc
@@ -94,12 +94,12 @@ class WebDragSourceAura : public MessageLoopForUI::Observer {
 // Utility to fill a ui::OSExchangeDataProviderAura object from WebDropData.
 void PrepareDragData(const WebDropData& drop_data,
                      ui::OSExchangeDataProviderAura* provider) {
-  if (!drop_data.plain_text.empty())
-    provider->SetString(drop_data.plain_text);
+  if (!drop_data.text.string().empty())
+    provider->SetString(drop_data.text.string());
   if (drop_data.url.is_valid())
     provider->SetURL(drop_data.url, drop_data.url_title);
-  if (!drop_data.text_html.empty())
-    provider->SetHtml(drop_data.text_html, drop_data.html_base_url);
+  if (!drop_data.html.string().empty())
+    provider->SetHtml(drop_data.html.string(), drop_data.html_base_url);
   if (!drop_data.filenames.empty()) {
     std::vector<ui::OSExchangeData::FileInfo> filenames;
     for (std::vector<WebDropData::FileInfo>::const_iterator it =
@@ -123,20 +123,26 @@ void PrepareDragData(const WebDropData& drop_data,
 // Utility to fill a WebDropData object from ui::OSExchangeData.
 void PrepareWebDropData(WebDropData* drop_data,
                         const ui::OSExchangeData& data) {
-  string16 plain_text, url_title;
-  GURL url;
-
+  string16 plain_text;
   data.GetString(&plain_text);
   if (!plain_text.empty())
-    drop_data->plain_text = plain_text;
+    drop_data->text = NullableString16(plain_text, false);
 
+  GURL url;
+  string16 url_title;
   data.GetURLAndTitle(&url, &url_title);
   if (url.is_valid()) {
     drop_data->url = url;
     drop_data->url_title = url_title;
   }
 
-  data.GetHtml(&drop_data->text_html, &drop_data->html_base_url);
+  string16 html;
+  GURL html_base_url;
+  data.GetHtml(&html, &html_base_url);
+  if (!html.empty())
+    drop_data->html = NullableString16(html, false);
+  if (html_base_url.is_valid())
+    drop_data->html_base_url = html_base_url;
 
   std::vector<ui::OSExchangeData::FileInfo> files;
   if (data.GetFilenames(&files) && !files.empty()) {
diff --git a/content/browser/web_contents/web_drag_dest_gtk.cc b/content/browser/web_contents/web_drag_dest_gtk.cc
index 3a2fc0d..20093f4 100644
--- a/content/browser/web_contents/web_drag_dest_gtk.cc
+++ b/content/browser/web_contents/web_drag_dest_gtk.cc
@@ -176,8 +176,9 @@ void WebDragDestGtk::OnDragDataReceived(
     if (target == ui::GetAtomForTarget(ui::TEXT_PLAIN)) {
       guchar* text = gtk_selection_data_get_text(data);
       if (text) {
-        drop_data_->plain_text =
-            UTF8ToUTF16(std::string(reinterpret_cast<const char*>(text)));
+        drop_data_->text = NullableString16(
+            UTF8ToUTF16(std::string(reinterpret_cast<const char*>(text))),
+            false);
         g_free(text);
       }
     } else if (target == ui::GetAtomForTarget(ui::TEXT_URI_LIST)) {
@@ -199,7 +200,7 @@ void WebDragDestGtk::OnDragDataReceived(
             // This is a hack. Some file managers also populate text/plain with
             // a file URL when dragging files, so we clear it to avoid exposing
             // it to the web content.
-            drop_data_->plain_text.clear();
+            drop_data_->text = NullableString16(true);
           } else if (!drop_data_->url.is_valid()) {
             // Also set the first non-file URL as the URL content for the drop.
             drop_data_->url = url;
@@ -209,9 +210,10 @@ void WebDragDestGtk::OnDragDataReceived(
       }
     } else if (target == ui::GetAtomForTarget(ui::TEXT_HTML)) {
       // TODO(estade): Can the html have a non-UTF8 encoding?
-      drop_data_->text_html =
+      drop_data_->html = NullableString16(
           UTF8ToUTF16(std::string(reinterpret_cast<const char*>(raw_data),
-                                  data_length));
+                                  data_length)),
+          false);
       // We leave the base URL empty.
     } else if (target == ui::GetAtomForTarget(ui::NETSCAPE_URL)) {
       std::string netscape_url(reinterpret_cast<const char*>(raw_data),
diff --git a/content/browser/web_contents/web_drag_dest_mac.mm b/content/browser/web_contents/web_drag_dest_mac.mm
index a502317..7c97892 100644
--- a/content/browser/web_contents/web_drag_dest_mac.mm
+++ b/content/browser/web_contents/web_drag_dest_mac.mm
@@ -239,17 +239,19 @@ int GetModifierFlags() {
 
   // Get plain text.
   if ([types containsObject:NSStringPboardType]) {
-    data->plain_text =
-        base::SysNSStringToUTF16([pboard stringForType:NSStringPboardType]);
+    data->text = NullableString16(
+        base::SysNSStringToUTF16([pboard stringForType:NSStringPboardType]),
+        false);
   }
 
   // Get HTML. If there's no HTML, try RTF.
   if ([types containsObject:NSHTMLPboardType]) {
-    data->text_html =
-        base::SysNSStringToUTF16([pboard stringForType:NSHTMLPboardType]);
+    data->html = NullableString16(
+        base::SysNSStringToUTF16([pboard stringForType:NSHTMLPboardType]),
+        false);
   } else if ([types containsObject:NSRTFPboardType]) {
     NSString* html = [pboard htmlFromRtf];
-    data->text_html = base::SysNSStringToUTF16(html);
+    data->html = NullableString16(base::SysNSStringToUTF16(html), false);
   }
 
   // Get files.
diff --git a/content/browser/web_contents/web_drag_dest_mac_unittest.mm b/content/browser/web_contents/web_drag_dest_mac_unittest.mm
index ec07e28..76fafbd 100644
--- a/content/browser/web_contents/web_drag_dest_mac_unittest.mm
+++ b/content/browser/web_contents/web_drag_dest_mac_unittest.mm
@@ -157,8 +157,8 @@ TEST_F(WebDragDestTest, Data) {
   [pboard setString:textString forType:NSStringPboardType];
   [drag_dest_ populateWebDropData:&data fromPasteboard:pboard];
   EXPECT_EQ(data.url.spec(), "http://www.google.com/");
-  EXPECT_EQ(base::SysNSStringToUTF16(textString), data.plain_text);
-  EXPECT_EQ(base::SysNSStringToUTF16(htmlString), data.text_html);
+  EXPECT_EQ(base::SysNSStringToUTF16(textString), data.text.string());
+  EXPECT_EQ(base::SysNSStringToUTF16(htmlString), data.html.string());
 
   [pboard releaseGlobally];
 }
diff --git a/content/browser/web_contents/web_drag_source_gtk.cc b/content/browser/web_contents/web_drag_source_gtk.cc
index 4e8518b..3572e75 100644
--- a/content/browser/web_contents/web_drag_source_gtk.cc
+++ b/content/browser/web_contents/web_drag_source_gtk.cc
@@ -85,14 +85,14 @@ void WebDragSourceGtk::StartDragging(const WebDropData& drop_data,
 
   int targets_mask = 0;
 
-  if (!drop_data.plain_text.empty())
+  if (!drop_data.text.string().empty())
     targets_mask |= ui::TEXT_PLAIN;
   if (drop_data.url.is_valid()) {
     targets_mask |= ui::TEXT_URI_LIST;
     targets_mask |= ui::CHROME_NAMED_URL;
     targets_mask |= ui::NETSCAPE_URL;
   }
-  if (!drop_data.text_html.empty())
+  if (!drop_data.html.string().empty())
     targets_mask |= ui::TEXT_HTML;
   if (!drop_data.file_contents.empty())
     targets_mask |= ui::CHROME_WEBDROP_FILE_CONTENTS;
@@ -183,7 +183,7 @@ void WebDragSourceGtk::OnDragDataGet(GtkWidget* sender,
 
   switch (target_type) {
     case ui::TEXT_PLAIN: {
-      std::string utf8_text = UTF16ToUTF8(drop_data_->plain_text);
+      std::string utf8_text = UTF16ToUTF8(drop_data_->text.string());
       gtk_selection_data_set_text(selection_data, utf8_text.c_str(),
                                   utf8_text.length());
       break;
@@ -192,7 +192,7 @@ void WebDragSourceGtk::OnDragDataGet(GtkWidget* sender,
     case ui::TEXT_HTML: {
       // TODO(estade): change relative links to be absolute using
       // |html_base_url|.
-      std::string utf8_text = UTF16ToUTF8(drop_data_->text_html);
+      std::string utf8_text = UTF16ToUTF8(drop_data_->html.string());
       gtk_selection_data_set(selection_data,
                              ui::GetAtomForTarget(ui::TEXT_HTML),
                              kBitsPerByte,
diff --git a/content/browser/web_contents/web_drag_source_mac.mm b/content/browser/web_contents/web_drag_source_mac.mm
index 875f892..f9e57a4 100644
--- a/content/browser/web_contents/web_drag_source_mac.mm
+++ b/content/browser/web_contents/web_drag_source_mac.mm
@@ -151,9 +151,9 @@ void PromiseWriterHelper(const WebDropData& drop_data,
 
   // HTML.
   if ([type isEqualToString:NSHTMLPboardType]) {
-    DCHECK(!dropData_->text_html.empty());
+    DCHECK(!dropData_->html.string().empty());
     // See comment on |kHtmlHeader| above.
-    [pboard setString:SysUTF16ToNSString(kHtmlHeader + dropData_->text_html)
+    [pboard setString:SysUTF16ToNSString(kHtmlHeader + dropData_->html.string())
               forType:NSHTMLPboardType];
 
   // URL.
@@ -206,8 +206,8 @@ void PromiseWriterHelper(const WebDropData& drop_data,
 
   // Plain text.
   } else if ([type isEqualToString:NSStringPboardType]) {
-    DCHECK(!dropData_->plain_text.empty());
-    [pboard setString:SysUTF16ToNSString(dropData_->plain_text)
+    DCHECK(!dropData_->text.string().empty());
+    [pboard setString:SysUTF16ToNSString(dropData_->text.string())
               forType:NSStringPboardType];
 
   // Custom MIME data.
@@ -375,7 +375,7 @@ void PromiseWriterHelper(const WebDropData& drop_data,
              owner:contentsView_];
 
   // HTML.
-  if (!dropData_->text_html.empty())
+  if (!dropData_->html.string().empty())
     [pasteboard_ addTypes:[NSArray arrayWithObject:NSHTMLPboardType]
                     owner:contentsView_];
 
@@ -439,7 +439,7 @@ void PromiseWriterHelper(const WebDropData& drop_data,
   }
 
   // Plain text.
-  if (!dropData_->plain_text.empty())
+  if (!dropData_->text.string().empty())
     [pasteboard_ addTypes:[NSArray arrayWithObject:NSStringPboardType]
                     owner:contentsView_];
 
diff --git a/content/common/drag_messages.h b/content/common/drag_messages.h
index 59ee6b3..7714570 100644
--- a/content/common/drag_messages.h
+++ b/content/common/drag_messages.h
@@ -29,8 +29,8 @@ IPC_STRUCT_TRAITS_BEGIN(WebDropData)
   IPC_STRUCT_TRAITS_MEMBER(referrer_policy)
   IPC_STRUCT_TRAITS_MEMBER(filenames)
   IPC_STRUCT_TRAITS_MEMBER(filesystem_id)
-  IPC_STRUCT_TRAITS_MEMBER(plain_text)
-  IPC_STRUCT_TRAITS_MEMBER(text_html)
+  IPC_STRUCT_TRAITS_MEMBER(text)
+  IPC_STRUCT_TRAITS_MEMBER(html)
   IPC_STRUCT_TRAITS_MEMBER(html_base_url)
   IPC_STRUCT_TRAITS_MEMBER(file_description_filename)
   IPC_STRUCT_TRAITS_MEMBER(file_contents)
diff --git a/ui/base/clipboard/scoped_clipboard_writer.cc b/ui/base/clipboard/scoped_clipboard_writer.cc
index 95cf505..5ecb43c 100644
--- a/ui/base/clipboard/scoped_clipboard_writer.cc
+++ b/ui/base/clipboard/scoped_clipboard_writer.cc
@@ -38,9 +38,6 @@ void ScopedClipboardWriter::WriteURL(const string16& text) {
 
 void ScopedClipboardWriter::WriteHTML(const string16& markup,
                                       const std::string& source_url) {
-  if (markup.empty())
-    return;
-
   std::string utf8_markup = UTF16ToUTF8(markup);
 
   Clipboard::ObjectMapParams parameters;
@@ -56,9 +53,6 @@ void ScopedClipboardWriter::WriteHTML(const string16& markup,
 }
 
 void ScopedClipboardWriter::WriteRTF(const std::string& rtf_data) {
-  if (rtf_data.empty())
-    return;
-
   Clipboard::ObjectMapParams parameters;
   parameters.push_back(Clipboard::ObjectMapParam(rtf_data.begin(),
                                                  rtf_data.end()));
@@ -139,9 +133,6 @@ void ScopedClipboardWriter::Reset() {
 }
 
 void ScopedClipboardWriter::WriteTextOrURL(const string16& text, bool is_url) {
-  if (text.empty())
-    return;
-
   std::string utf8_text = UTF16ToUTF8(text);
 
   Clipboard::ObjectMapParams parameters;
diff --git a/webkit/glue/webclipboard_impl.cc b/webkit/glue/webclipboard_impl.cc
index b782cd2..eb71a61 100644
--- a/webkit/glue/webclipboard_impl.cc
+++ b/webkit/glue/webclipboard_impl.cc
@@ -235,8 +235,10 @@ void WebClipboardImpl::writeDataObject(const WebDragData& data) {
 
   WebDropData data_object(data);
   // TODO(dcheng): Properly support text/uri-list here.
-  scw.WriteText(data_object.plain_text);
-  scw.WriteHTML(data_object.text_html, "");
+  if (!data_object.text.is_null())
+    scw.WriteText(data_object.text.string());
+  if (!data_object.html.is_null())
+    scw.WriteHTML(data_object.html.string(), "");
   // If there is no custom data, avoid calling WritePickledData. This ensures
   // that ScopedClipboardWriterGlue's dtor remains a no-op if the page didn't
   // modify the DataTransfer object, which is important to avoid stomping on
diff --git a/webkit/glue/webdropdata.cc b/webkit/glue/webdropdata.cc
index 73c89fa..398bc31 100644
--- a/webkit/glue/webdropdata.cc
+++ b/webkit/glue/webdropdata.cc
@@ -31,14 +31,16 @@ WebDropData::FileInfo::FileInfo(const string16& path,
 }
 
 WebDropData::WebDropData(const WebDragData& drag_data)
-    : referrer_policy(WebKit::WebReferrerPolicyDefault) {
+    : referrer_policy(WebKit::WebReferrerPolicyDefault),
+      text(NullableString16(true)),
+      html(NullableString16(true)) {
   const WebVector<WebDragData::Item>& item_list = drag_data.items();
   for (size_t i = 0; i < item_list.size(); ++i) {
     const WebDragData::Item& item = item_list[i];
     switch (item.storageType) {
       case WebDragData::Item::StorageTypeString: {
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeText)) {
-          plain_text = item.stringData;
+          text = NullableString16(item.stringData, false);
           break;
         }
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeURIList)) {
@@ -51,7 +53,7 @@ WebDropData::WebDropData(const WebDragData& drag_data)
           break;
         }
         if (EqualsASCII(item.stringType, ui::Clipboard::kMimeTypeHTML)) {
-          text_html = item.stringData;
+          html = NullableString16(item.stringData, false);
           html_base_url = item.baseURL;
           break;
         }
@@ -73,7 +75,9 @@ WebDropData::WebDropData(const WebDragData& drag_data)
 }
 
 WebDropData::WebDropData()
-    : referrer_policy(WebKit::WebReferrerPolicyDefault) {
+    : referrer_policy(WebKit::WebReferrerPolicyDefault),
+      text(NullableString16(true)),
+      html(NullableString16(true)) {
 }
 
 WebDropData::~WebDropData() {
@@ -87,15 +91,16 @@ WebDragData WebDropData::ToDragData() const {
   DCHECK(file_contents.empty());
   DCHECK(file_description_filename.empty());
 
-  // TODO(dcheng): We need a way to distinguish between null and empty strings.
-  if (!plain_text.empty()) {
+  if (!text.is_null()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = WebString::fromUTF8(ui::Clipboard::kMimeTypeText);
-    item.stringData = plain_text;
+    item.stringData = text.string();
     item_list.push_back(item);
   }
 
+  // TODO(dcheng): Do we need to distinguish between null and empty URLs? Is it
+  // meaningful to write an empty URL to the clipboard?
   if (!url.is_empty()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
@@ -105,11 +110,11 @@ WebDragData WebDropData::ToDragData() const {
     item_list.push_back(item);
   }
 
-  if (!text_html.empty()) {
+  if (!html.is_null()) {
     WebDragData::Item item;
     item.storageType = WebDragData::Item::StorageTypeString;
     item.stringType = WebString::fromUTF8(ui::Clipboard::kMimeTypeHTML);
-    item.stringData = text_html;
+    item.stringData = html.string();
     item.baseURL = html_base_url;
     item_list.push_back(item);
   }
diff --git a/webkit/glue/webdropdata.h b/webkit/glue/webdropdata.h
index 0da3e07..9dd5571 100644
--- a/webkit/glue/webdropdata.h
+++ b/webkit/glue/webdropdata.h
@@ -13,6 +13,7 @@
 #include <string>
 #include <vector>
 
+#include "base/nullable_string16.h"
 #include "base/string16.h"
 #include "googleurl/src/gurl.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebReferrerPolicy.h"
@@ -61,12 +62,12 @@ struct WEBKIT_GLUE_EXPORT WebDropData {
   string16 filesystem_id;
 
   // User is dragging plain text into the webview.
-  string16 plain_text;
+  NullableString16 text;
 
   // User is dragging text/html into the webview (e.g., out of Firefox).
   // |html_base_url| is the URL that the html fragment is taken from (used to
   // resolve relative links).  It's ok for |html_base_url| to be empty.
-  string16 text_html;
+  NullableString16 html;
   GURL html_base_url;
 
   // User is dragging data from the webview (e.g., an image).
diff --git a/webkit/glue/webdropdata_win.cc b/webkit/glue/webdropdata_win.cc
index 049df9e..9dd8306 100644
--- a/webkit/glue/webdropdata_win.cc
+++ b/webkit/glue/webdropdata_win.cc
@@ -25,11 +25,19 @@ void WebDropData::PopulateWebDropData(IDataObject* data_object,
   ui::ClipboardUtil::GetFilenames(data_object, &filenames);
   for (size_t i = 0; i < filenames.size(); ++i)
     drop_data->filenames.push_back(FileInfo(filenames[i], string16()));
-  ui::ClipboardUtil::GetPlainText(data_object, &drop_data->plain_text);
-  std::string base_url;
-  ui::ClipboardUtil::GetHtml(data_object, &drop_data->text_html, &base_url);
-  if (!base_url.empty()) {
-    drop_data->html_base_url = GURL(base_url);
+  string16 text;
+  ui::ClipboardUtil::GetPlainText(data_object, &text);
+  if (!text.empty()) {
+    drop_data->text = NullableString16(text, false);
+  }
+  string16 html;
+  std::string html_base_url;
+  ui::ClipboardUtil::GetHtml(data_object, &html, &html_base_url);
+  if (!html.empty()) {
+    drop_data->html = NullableString16(html, false);
+  }
+  if (!html_base_url.empty()) {
+    drop_data->html_base_url = GURL(html_base_url);
   }
   ui::ClipboardUtil::GetWebCustomData(data_object,
       &drop_data->custom_data);