Separate LineBreaker from RenderBlockLineLayout

As part of my RenderBlockLineLayout refactoring campaign (tracked under
issue 316347) in this patch, I'm separating LineBreaker class into its
own file. Since BreakingContext::handleEndOfLine() implementation is not
inline, I moved it to BreakingContext.cpp in order to avoid linking errors.

BUG=336293

Review URL: https://codereview.chromium.org/142323003

git-svn-id: svn://svn.chromium.org/blink/trunk@165539 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Form association by HTML parser should not work if the form element is not in the document tree.

The new behavior matches to the standard, IE11, and Firefox 26.

Note that FormAssociatedElement::associateByParser can't be called in
the FormAssociatedElement constructor because associateByParser
calls virtual functions internally.

BUG=256797
TEST=automated.

Review URL: https://codereview.chromium.org/144773002

git-svn-id: svn://svn.chromium.org/blink/trunk@165540 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Verify tighter PARSING_MEDIA_SEGMENT entrance constraint

Updates MSE SourceBuffer mode layout test to verify that
setting the mode fails when half of a media segment is
appended instead of much more. Tight conformance on a
per-parser-basis is left to WebSourceBuffer
implementations and their unit tests.
Also adds similar verification for SourceBuffer timestampOffset.

R=acolwell@chromium.org
BUG=334127
TEST=The updated layout test passes locally on Linux.

Review URL: https://codereview.chromium.org/131763005

git-svn-id: svn://svn.chromium.org/blink/trunk@165541 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove dead code in Source/core/editing/.

This CL removes the following unused code:
- ApplyStyleCommand::nodeFullyUnselected
- CharacterIterator::string
- CompositeEditCommand::insertLineBreak
- CompositeEditCommand::isCreateLinkCommand and an override
- CompositeEditCommand::shouldRetainAutocorrectionIndicator and an override
- DeleteSelectionCommand::calculateEndingPosition declaration
- DeleteSelectionCommand::insertPlaceholderForAncestorBlockContent declaration
- EditingCommand::isEditCommandComposition
- EditingStyle::EditingStyle(const CSSStyleDeclaration*)
- EditingStyle::create(const CSSStyleDeclaration*)
- EditingStyle::setStyle
- EditingStyle::shouldUseFixedDefaultFontSize
- IndentOutdentCommand::indentRegion declaration
- InsertLineBreakCommand::insertNodeAfterPosition
- InsertLineBreakCommand::insertNodeBeforePosition
- InsertListCommand::insertList
- InsertTextCommand::InsertTextCommand(Document&, const String&, PassRefPtr<TextInsertionMarkerSupplier>)
- InsertTextCommand::create(Document&, const String&, PassRefPtr<TextInsertionMarkerSupplier>)
- InsertTextCommand::deleteCharacter declaration
- InsertTextCommand::m_markerSupplier
- ReplaceSelectionCommand::handlePasteAsQuotationNode declaration
- SetSelectionCommand class
- SpellCheckRequester::isStarted
- SpellChecker::misspelledWordAtCaretOrRange
- TextInsertionMarkerSupplier class
- TypingCommand::smartDelete
- WordAwareIterator::range
- positionOutsideTabSpan in htmlediting.{cpp,h}

BUG=none
TEST=none; no behavior changes

Review URL: https://codereview.chromium.org/144233007

git-svn-id: svn://svn.chromium.org/blink/trunk@165542 bbb929c8-8fbe-4397-9dbb-9b2b20218538