✅ Resolve some flakiness in e2e tests

[cvializ]

@estherkim can you take a look at this branch and see if it resolves some of the flakiness you were seeing in your test runs? I noticed 2 problems in my investigation

1. Selenium's window setRect when headless will get close but not reach the actual value passed to the function. I solved this by not configuring the browser to use headless mode.
2. Window sizes below 800px can sometimes refuse to be set. I don't know why. I updated the tests as best I could to use the wider window.

@sparhami some of the tests just don't pass even after making these changes. Can you take a look and make sure that they are expecting the correct values?

[estherkim]

See if this solves the resize problem?

  /**
   * Resize the window to a target client size
   * @param {!Rect} targetClientRect
   */
  async setWindowRect(targetClientRect) {
    const windowRect = await this.driver.manage().window().getRect()
        .catch(e => {this.logError_(e);});

    const clientRect = await this.driver.executeScript(() => {
      return {height: window.innerHeight, width: window.innerWidth};
    });

    // Take window borders into account when calculating the new window size
    const targetWindowRect = {
      height: windowRect.height - clientRect.height + targetClientRect.height,
      width: windowRect.width - clientRect.width + targetClientRect.width,
    };

    const actualWindowRect =
    await this.driver.manage().window().setRect(targetWindowRect)
        .catch(e => {this.logError_(e);});

    if (actualWindowRect.width != targetWindowRect.width ||
      actualWindowRect.height != targetWindowRect.height) {
      this.logError_(new Error(
          'Failed to resize window. ' +
          `Expected: {height: ${targetWindowRect.height}, ` +
          `width: ${targetWindowRect.width}}. ` +
          `Actual: {height: ${actualWindowRect.height}, ` +
          `width: ${actualWindowRect.width}}.`
      ));
    }
  }

[cvializ]

Discussed offline: didn't help

[estherkim]

Carlos, I thought you saw assertion errors, not resize errors. That would mean that the resize actually worked.

[estherkim]

To make sure the resize error was actually thrown, it would need this -

 logError_(e) {
    throw new Error(e.message);
  }

[cvializ]

There are more timeouts with this method. The tests pass consistently with this PR, barring some Selenium session ID errors

[sparhami]

Does this one need to be skipped? I seem to be able to run it fine locally.

[cvializ]

You're right, I unskipped it

[sparhami]

It looks like the vertical tests are legitimately failing dues to snapping in the vertical axis being slightly off. Seems to be a rounding error somewhere, but seems to be a bug in Chrome. Seems like it may have surfaced when the viewport size changed.

[cvializ]

I'll keep it skipped for now so we have a more stable test field, and we can investigate and unskip. Let me know if it needs any other changes before Approval